I advocate for the rights of all people to live as, and be, whomever or whatever they choose to be so long as they don't expect to be put on a pedestal and force us all to celebrate their 'differences' whilst demanding all their whims be met.
To each his own. Live and be who you want so long as you do no harm to others. But that's not what this is.
Most liberals will try to screech you down as transphobic and intolerant if you oppose biological men competing against women and that's the sort of rhetoric that ultimately ends up breeding contempt and retaliation with words like "thing." It's not transphobic (is that not insulting language that should be muted?) to oppose this, it's moral common sense.
It should never be an "I'll act this way, but only if you act that way" scenario. This whole trans in women's sport thing is all kinds of WRONG and it's harming women athletes in a great many ways so if you do actually oppose it you should be voicing that on principle regardless of what others say.
If you truly believe it's wrong you should be saying it's wrong don't you think? If more people did that we wouldn't be in this growing situation and on the slippery slope we are now on whereby women's sport could be lost forever if people don't speak out.