I didn't say it wasn't understandable, just that it's a very dumb move from Eddie.
If someone looking beaten up to hell says eloquently how something is incredibly dangerous and has to be destroyed for the greater good, it is probably an idea to listen to them. Or at least not immediately stick your hand in the goo, but maybe run some tests on it.
(But the "wanting to prove him wrong" thing is probably why Eddie does it. Part of his monologue when the suit's doing it's stuff is how Peter managed it, overlooking the bit where Peter told him he barely managed, even with superpowers.)