I'm a financially motivated beastmaster. I don't take PTs often because, well, a dozen beastmen and kindred seals per evening for me sounds better than sharing them with a PT. Plus there's the coffers
But that aside, its a perception issue. Much like SMN, BST and DRG, a lot of people filter out pet damage and don't see the contribution a BST is making to the PT with his pet, they just see his damage.
Then there's the EXP penalty thing, players can't be bothered to learn and understand that it is ONLY when we charm a mob higher level than ourselves or the PT leader that an EXP penalty takes place. Some people think it always happens no matter what.