apparently they spoil very quickly if not frozen immediately, if there is no market they cant do anything witht ehpeaches. also the trees will attract alot of pests if its left unattended.

That (in their view) would be even worse, then peaches would become associated with the homeless and lose even more value!

The issue is that the idea of destroying product to protect its value is counter to anything good or reasonable.

Cost to harvest peaches to freely give to homeless dudes: very non-zero

Cost to burn peach trees: zero

This might surprise you, but you can give food to homeless people right now. You don't need to wait for some peach-related mishap in California to do so.

And who is going to pay to water, tend, pick. And ship these to the homeless?