Basically, yeah.  They are co-workers with conflicting personalities who don't know each other well enough for camaraderie to counteract it.  In addition, Gambit is fairly sexually threatening in a kinda douchey way, whereas Sean is a little awkward with women, so some of it is jealousy.  In addition, and this is probably the biggest thing, Remy feels no particular gratitude or reverence for Sean...has no desire to learn from him.  That makes Sean feel less important.