The debate seems to be around whether the word dyslexia should be used, but the condition --- however named --- exists anyway. The proposed phrase "struggling with reading comprehension" is no less broad, or actually more broad, than _dyslexia_, and in my opinion brings no additional value to the situation.
I've known a person diagnosed with Dyslexia, and he was simultaneously one of the most well-read, eloquent person I'd known, and the most struggling with spelling. Even words he had to write daily (being a teacher and all), he couldn't spell with high accuracy.
If you tell me, he was just "struggling" with spelling, that's no different than telling me a myopic person is just "struggling" to see, or a person with a club foot is just "struggling" to walk.
Of course, I don't object that there are difficulties in the diagnosis or even a precise definition of dyslexia. But, to me, that sounds like we need more research to understand what's happening. If you want me to believe that the condition alltogether doesn't exist, I'd like to see some more evidence.