Hard agree. I'm not dyslexic, but I also occasionally mark text to keep progress, especially if it's a long piece. And if I really want to copy that text, I will, sometimes just out of spite that you're trying to outsmart me, and I'm more likely to leave your site sooner too.
Also, while we're at it, can you please leave scrolling behaviour alone and not override it? I have a nice mouse that lets me scroll as fast or as slow as I want to. In some rare cases with a fancy UI where one wheel notch scrolls a whole page I agree that overriding the behaviour is warranted. In all other cases just FUCKING LEAVE SCROLLING AS IS (as handled by the OS and the browser) and don't try to be fancy; if you try to be fancy for no particular reason, I'm more likely to leave your site ASAP rather than prefer it over other sites.