I think hedonism can be defended, but only if tempered by the understanding that all is one, and that if we cause pain and suffering in the pursuit of hedonistic pleasure, we cause suffering to ourselves which is the opposite of the hedonistic goal.

If understood in this way, harming another for your pleasure is to plant thorns in your own bed.

Hedonism has got an unfair reputation, I think. There exists a mature understanding of hedonism, that is not "sinful" at all. On the contrary, it seeks the highest good and maximal pleasure, for everyone and everything. In fact, it could be argued that seeking maximum pleasure for all beings is the ultimate moral imperative.