I wanted to quote TKGS, of whose post I approve, but the width of the text on both posts 2 and 3 make that difficult. I hope Matthew or someone will fix that. Maybe it's just my screen?
In the meantime, yes: Why should any Catholic care about what an apostate says, an apostate who actually chose to adopt the name of Muhammed? It's bad enough when people affiliate with heretical religions. However, I am particularly offended when people choose for a name an identifier which forces the rest of the world to acknowledge that heresy and that apostasy over and over. (I know a cradle Catholic like that; she wandered into Hinduism for a long time, has reverted to the Catholicism of her birth, but has kept her adopted Hindu name. Why? Why should we have to address her by such a name? I find this very offensive.)