Of course, Picard could be the Dr. Belloq sort of amateur archaeologist, rather than the Dr. Jones sort - if he can't have this Promellian treasure chest, then nobody else can, either! He'll just rationalize his childish pride by claiming that removing the ship will be the best way to remove others' unhealthy interest in it.
I... don't think that's an accurate comparison. For one thing, Belloq was no "amateur" archeologist. He had knowledge of language that Indy lacked ("you could warn them if only you spoke hovitos") and was able to convince the nazis to work with him. In fact, he had a great respect towards his find when he wanted to make sure that the Ark was indeed the genuine deal rather than take his payment and leave. He wanted to see it for himself.
Indy on the other hand was willing to blow up the Ark with a freaking rocket launcher. Belloq knew Indy wouldn't do it so he called his bluff.