I would say it is not necessary to label your FC as LGBTQA+ friendly and I would say it could potentially be a detriment, of which I will explain why.
Throughout this thread, there has been numerous times that people have joined LGBTQA+ friendly FCs, only to see hatred and insults etc. Whilst I do not remember anyone being specific as to what insults are being used, I would postulate that it did not necessarily start as LGBTQA+ hate, it just went in that direction, as is what is generally portrayed. You do not agree with me, you must be wrong on everything mentality.
By labelling your FC as LGBTQA+ friendly, you are likely to attract more people that fit into that labelling, the problem is, that is all you could potentially have in common. There could be a discussion on something completely unrelated, someone disagrees, gets the whole things of, you aren't a true LGBTQA+ speech (Not true Scotsman Fallacy) and it explodes from there.
Another line it could go down is some people get offended by the smallest things, say something they do not agree with, you offend them and they have a tantrum.
Whilst I am not part of the Alphabetti Spaghetti, I would still rather be around people who have similar interests and a similar sense of humour. By finding people that you do get on with, are friendly with etc. you are more likely to find out that, if it does come out that you fit a label, they are going to be more accepting of you.
To add to this, if someone was to come up to me and introduce themselves as 'Hey, I'm X and I am LGBT', I would instantly think, I really do not care, I just want to know what your personality is like and straight away, it is not looking good. This might be my biased opinion, but noone actually cares....until you start shoving it down our throats. People put too much importance on their gender identity and how it shapes their life when, in reality, noone really cares.
I will say again, this is mainly pure speculation, feel free to correct me if you feel the need.