The thing is, other characters (a) talk smack about Tom Bombadil, and (b) readily admit that they’ve never met the guy and don’t know much about him.
But whenever we actually see Tom, he’s pretty much the most practical and interested guy this side of Superman: he shows up to save our heroes, and then tells them how to summon him if they need him again – which they do, at which point he of course shows up again to get the job done – and he asks them relevant questions when he’s not busy giving them useful equipment and magic weapons.
And so I figure it’s a Who-Are-You-Going-To-Believe-Me-Or-Your-Lying-Eyes thing.