Usually

I haven't clicked nor have the time atm to do so, but

Usually when anyone says that, they mean to separate BL and GL "psychologically", but not deny that MBL or FGL is bad. And then we get into hairsplitting terms:

MG: p(a)edophilia
MB: pederasty [*]
FG: korephilia
FB: Stifler's Mom, but, seriously, I don't know what it's supposed to be called when we tell each coupling combination apart.

[*] pederasty never has an A because the Greek root is slightly different.

Now, is that relevant or necessary??

It depends completely on what your intentions are in describing us. I would think that in a discussion about legality or about "seek help" or about "your kids are in danger", it should be irrelevant. In certain discussions about aetiology or more neutral description, however, it might be relevant.

But since when have "relevant" and "necessary" played a role when the mainstream deals with us??