Hello,
I'm transgender (FTM), and I don't think it's fair. You can say it's not fair without insulting people you don't understand, people. If a sport is really dependent on strength like that, the MTF gal has a natural advantage. Some people might argue that it's unfair that Michael Phelps is double jointed, but there is a reason many sports aren't co-ed. My brain (according to a small-scale study, transgender people had the brain of the gender they identified as, which is rather the most important organ, wouldn't you say? As far as I know, the study hasn't been scaled up yet but I haven't looked for updates) might be male, but my strength distribution is female, whether I like it or not. Obviously I can workout with certain goals in mind, but this lady's goals are to be strong in a sport where men have an advantage, and ergo she would kick my arse.
There are lots of trans folks who don't take hormones for various reasons including health issues, etc., but sometimes it's a professional choice, like they're a musician and they don't want to send their singing voice through a second puberty. Which is totally valid and their decision, but if this lady isn't on E it's extra unfair, I think.
Tl;dr sex is parts and gender is mind, and if I was competing in a sport where girls have an advantage as a trans man, I'd bow out. I underatand why some trans folks don't want to be out (read this comments section and the insults and it's not hard to see why), but your past doesn't get erased because it was painful, and unless you were able to take hormone suppressants as a teenager so you didn't go through the wrong puberty, which most trans people don't get to do because they're minors and society deems them unfit to have control over their bodies, your body matured the wrong way, like it or not. I have hips built to accommodate twins, and no amount of T is going to whittle them down. This gal has superior upper body strength, and since she obviously still exercises it, she's not losing it, and doesn't want to ...which is fine for her personally, but unfair in a gendered competition that is gendered based on physical advantages. If it was gendered for no logical reason, it wouldn't matter.