I like to think of myself as quite open minded and I'm willing to acknowledge that someone should be allowed to change the gender they choose to present to the world and identify as.
However that doesn't change the fact that Hubbard was born and lived many years biologically as a man and still has the genetic makeup of a male (XY chromosome, muscle density, etc).
To me that constitutes an entirely unfair advantage over biological females since it would likely make them uncompetitive against a trans-woman IMO.
To that end allowing trans-women to compete in female events is simply unfair IMO.
There are very valid reasons we separate men and women in sports. Similarly we divide weight lifters based on their weight as everyone accepts that someone who weighs more is likely to be physically stronger.
In the same way I think everyone would also accept that men are physically stronger that women particularly at the same weight.
In fact does anyone think that men don't have an advantage when it comes to physical events like without weight lifting, boxing, athletics, etc compared to women?