As noted earlier, a spell-like ability is subject to dispelling (provided the spell it duplicates is subject to dispelling). When a spell-like ability can be dispelled (as most of them are) one can effectively counter them with a dispel magic spell. While spell-like abilities are not normally subject to counterspells, dispel magic is not really a counterspell. When you use dispel magic as a counterspell, what you're really doing is casting a quick, targeted dispel effect at the correct moment to negate the enemy spell and not creating an opposite magical effect that cancels your enemy's spell.
Rules of the game,伪反,但是确实是反