Absolutely. The "being gay is a choice" line is doubly homophobic- once because it's often not a choice, and twice because even if it was, that doesn't mean it'd be wrong to make that choice. But, two things:

One, in practice there is oppression based on the idea that gay people can choose to be straight, like gay conversion camps, and it's harmful to validate the idea that they could work, even if you're clear that you don't agree with their aim.

And two, it imples that all the gay people who have suffered oppression have, to some extent, chosen that. And while that is true for some courageous or determined people, there are many for who it's not.