Under Article 11 ECHR, the member states have the positive obligation to guarantee that the members of associations are able to hold meetings without having to fear physical violence from their opponents. Their role is not to remove the cause of tension by eliminating pluralism, but to ensure that the competing groups tolerate each other.

This decision is linked to several attempts to register LGBT associations with the Russian authorities of different cities.
In all cases, the authorities rejected the application of the associations on similar grounds, namely that the activities of the associations were terrorist and that they were incompatible with basic morality as they may lead to increasing the number of citizens belonging to sexual minorities, thereby undermining the conceptions of good and evil, of sin and virtue established in society.
All applicants appealed in vain, the various courts finding that the previous decisions had been lawful, well reasoned and justified.
The applicants complained that the refusals to register the organisations had violated their freedom of association, guaranteed by Article 11 ECHR.
The Government argued that the associations were not registered, and, therefore, couldn’t submit an application to the Court. The Court recalls that it has frequently recognized the standing of unregistered or dissolved organizations to submit an application without enquiring into whether the organization is considered to legally exist in some form under the national law after its dissolution or refusal of registration (points 115-116).
The Government submitted then that the refusals of registration had not amounted to an interference with the applicants’ rights under Article 11 ECHR. In the alternative, they submitted that the refusals had been lawful and justified. 
The Court reiterates that the ability to establish a legal entity in order to act collectively in a field of mutual interest is one of the most important aspects of freedom of association, without which that right would be deprived of any meaning (point 142).
Then the Court examines the aims alleged by the Government to refuse the registration, which are: to protect society’s moral values and the institutions of family and marriage; to protect Russia’s sovereignty, safety and territorial integrity, which they considered to be threatened by a decrease in the population caused by the activities of LGBT associations; to protect the rights and freedoms of others; and to prevent social or religious hatred and enmity, which in the Government’s view could be incited by the activities of LGBT associations and which might lead to violence (point 151).
The Court dismisses the government's first three arguments. (points 152-159) but agrees that the declared aim of preventing hatred and enmity corresponds to the legitimate aim of prevention of disorder and proceeds on the assumption that the contested measures pursued that aim (point 160). It must be noted that the risk of hatred and enmity capable of leading to disorder was apparently inferred by the national authorities in the present case from their belief that the majority of Russians disapproved of homosexuality and resented any display of same-sex relations or promotion of LGBT rights. They considered that the applicants might potentially become victims of aggression by persons who disapproved of homosexuality (point 161). 
The Court reiterates that a purely negative conception of Article 11 ECHR – not to interfere – would not be compatible with the purpose of Article 11 ECHR or with that of the Convention in general. There may thus be positive obligations to secure the effective enjoyment of the right to freedom of association. Accordingly, it is incumbent upon public authorities to guarantee the proper functioning of associations. Their members must be able to hold meetings without having to fear that they will be subjected to physical violence by their opponents. The positive obligation to secure the effective enjoyment of the right to freedom of association and assembly is of particular importance for persons holding unpopular views or belonging to minorities, because they are more vulnerable to victimization. Accordingly, the role of the authorities in such circumstances is not to remove the cause of tension by eliminating pluralism, but to ensure that the competing groups tolerate each other. In such circumstances, the Court cannot accept that the refusal to register the applicant organisations was “necessary in a democratic society”. There has therefore been a violation of Article 11 ECHR (points 161-165).
The applicants also complained that the refusals to register the applicant organisations amounted to discrimination on grounds of sexual orientation. They relied on Article 14 ECHR. 
The Court has accepted that a non-governmental organization could claim to be a victim of a violation of Article 14 ECHR on account of sexual orientation (point 171). The applicant organisations may therefore claim to be victims of a violation of Article 14 ECHR on grounds of sexual orientation. (point 172).
It is the Court’s established case-law that in order for an issue to arise under Article 14 ECHR there must be a difference in the treatment of persons in relevantly similar situations. But if the Contracting State enjoys a margin of appreciation in assessing whether and to what extent differences in otherwise similar situations justify a different treatment, with specific regard to differences in treatment based on sexual orientation, the Court has held that the State’s margin of appreciation is a narrow one (point 179). The Court concludes that the foregoing findings give rise to a violation of Article 14 ECHR taken in conjunction with Article 11 ECHR (point 183).
Direct to the judgement (hudoc.echr.coe.int)