There is a thread on FWR entirely devoted to the collation of stories about any crimes trans people commit. Anyone who finds anything in the news, in the UK or further afield pastes the story in for others to comment on, and it certainly used to regularly be at the top of the board.
Now, you may not think this a problem, but if you are fine with this, then to be logically consistent you must agree that it is perfectly fine that any other forum out there start up and devote a thread entirely dedicated to the collation and recording of any crimes lesbians commit, and commentary on what should be done to address this pressing social problem.
And this is a very good indication that this thread is posted - and in some cases contributed to - in extremely bad faith.
THIS is your example of a transphobic thread? I'll offer a clearer picture. The thread in question is titled 'This Never Happens'. It's a direct refutation of the weak reasoning offered by trans rights activism - a claim not only devoid of basis but actually flying in the face of extensive evidence to the contrary - as to why women should meekly cede over our protected spaces without objection or argument.
The thread is a sequence of ongoing, individual cases which evidence what feminists have warned about almost from the beginning: that this does happen, and it happens with alarming and depressing regularity.
In which case, your self-professed logical deduction is in fact completely illogical. The LGBA rights movement never claimed for rights over and above those of others. Their reasonable requests to live without persecution and discrimination, and to order their lives and marry the partner of their choice. They've never asked for anything the rest of society hasn't always taken for granted, and they haven't attempted to stampede over or colonise the rights of any other vulnerable group (and yes, women's biology makes us so.
In which case, your suggestion that they'll be coming for other groups next and collating their crimes makes zero sense. Women are at risk when sharing mixed sex spaces with biological males. That thread provides ample ongoing evidence as to the fact, and to the reasons why that's the case.
Lesbians are women. Why would other women have a vested interest in keeping them out of an exclusively female space.
Note, too, how trans men are not coming after men in the same way, hence they are not subject to the same depth of discussion on that board.
The reasons are hardly difficult to deduce.