This is 100% my personal experience also. Even on HN last week someone said I should try to be a "better human" and compared my suggestion that maybe someone might oppose transgender women in women's spaces for reasons other than pure hatred or phobia of trans people, to segregation of blacks and whites. It's just absolutely impossible to have any disagreement with them without them trying these inane mob bully tactics. Being outraged should not be your only argument.
Take the case of Fallon Fox (https://en.wikipedia.org/wiki/Fallon_Fox): a mixed martial artist transgender woman (who didn't even disclose she used to be a he while she was competing against women), or Laurel Hubbard, the New Zealand transgender olympic weightlifter in the news this week. Even mentioning these cases which clearly have more to them than pure hatred or phobia of trans people, still get lambasted with abuse.
What's really frustrating is that they don't really listen to what you actually say, but instead "read between the lines" and assume everything you say is just a ruse hidden behind some immense hatred and bigotry. How about no? Just take what I say at face value. No, I'm not full of hate. Yes, I know being transgendered must be hard. Yes, I do know some transgendered people (why is this relevant?). Yes, I am cisgendered myself. No, I really do think transgender women have an advantage in combat sports. No, again, I'm not full of hate... It's quite ridiculous.
... OP was flagged because...?