If you define 'trans rights' as the right to redefine 'women and girls' so that the terms have nothing to do with biological sex but are all about sexist gender stereotypes about femininity and/or assumed comfort with sexist gender roles for women, then it's very difficult not to be against such 'trans rights' as they are directly ladled out from the hard-won rights of female people. And would ultimately make seeing sexism almost impossible, as the statistics on that would not be collected, the words to define the affected group would not exist and so on.
If you define 'trans rights' as the right not to be discriminated against in employment or education and not to be harassed or treated with violence and so on, then nobody here is opposed to those rights.
Because words now seem to mean anything someone wants them to mean, we don't know what we might be debating when someone says 'anti trans'.
I am for women's rights, the old-fashioned type, and currently I see those rights being seen as unnecessary and up for repurposing by the more deserving groups.
What used to be called 'women and girls' are now expected to accept themselves as 'cisgender women and girls', the more privileged sub-group in the new gender identity class of 'women and girls'.
We are not allowed to define ourselves as 'women and girls' simply because we are female people. We are told that we must possess an innermost abstract identity, not based on our sex or on what it is like to live as people of that sex, and any attempt to define that innermost 'gendered soul' in practice turns into sexist stereotypes.
This new approach will cause more and more problems the more it is used. Some minor examples:
I saw an article, some time ago, on how "becoming a parent" causes a fall in employed parents' earnings. But that is incorrect, as it's becoming a mother which causes that fall, on average, not becoming a father (fathers see their earnings rise, on average). When 'inclusive language' turned 'mother' into 'parent', what that article argued stopped being true.
I have also seen numerical errors on sites discussing specific female health conditions and their prevalence, because the information was altered to be more 'inclusive' to those who don't identify as women or girls but who are still female. So something that affects, say, 10% of women, was then turned into a condition affecting 10% of all people. This is just an arithmetic error, but I have seen it repeated three times now.
If we can't define the group something affects properly, then we can't collect and analyse evidence about it properly, either.
Similar problems apply in some criminal statistics where areas of crime which are very male-dominated suddenly appear to experience an increase in female perpetrators, and the reason is not that women are suddenly committing more sex crimes against, say, children, but that more male perpetrators are identifying as women. If collecting statistics on the basis of self-identification becomes more common, any policies based on them are likely to be based on erroneous data.