This assumes critics of Mohammed are attempting to accurately evaluate his psychology according to modern medical convention. They are probably not. It's probably most often a rhetorical gut-feeling condemnation of what they perceive to be abuse against a child. In this respect, Mohammed is a "pedophile" - the go-to insult that carries enough condemning power to quickly and succinctly articulate their contempt for Mohammed; who, by Islam's own accounts, raped a child.
Child molester, child abuser, child rapist, sex offender, nonce, kiddy fiddler, pedophile, all of the above. Pick an option, because the difference is negligible in most people's eyes. Pedophile is a good word in this case. It puts Mohammed clearly in the right stratum of moral depravity that his actions have earned him a place in.
I'm beating a dead horse here, but 1. Muhammad "engaged" with Aisha after she reached puberty (by account of nearly all relevant Hadith) so technically she was not a child, hence Muhammad could not have been a child molestor. 2. I've already explained why pedaphile is an incorrect terms to use. 3. I'm tired debating this, please let this topic die.