Because of national laws about gay marriage differencing greatly and there being a lot of countries where religion plays a serious role in politics i wanted to share with you the actual legal articles, since these are quite easy to understand and the eu has these laws in all languages as well.

This is from the English version of the CHARTER OF FUNDAMENTAL RIGHTS OF THE EUROPEAN UNION

Article 11
Freedom of expression and information

1 Everyone has the right to freedom of expression. This right shall include freedom to hold opinions and to receive and impart information and ideas without interference by public authority and regardless of frontiers.

Article 12
Freedom of assembly and of association

1 Everyone has the right to freedom of peaceful assembly and to freedom of association at all levels, in particular in political, trade union and civic matters, which implies the right of everyone to form and to join trade unions for the protection of his or her interests.

Article 21
Non-discrimination

1 Any discrimination based on any ground such as sex, race, colour, ethnic or social origin, genetic features, language, religion or belief, political or any other opinion, membership of a national minority, property, birth, disability, age or sexual orientation shall be prohibited.

tl;dr No, it is not legal.