Not a reason, but there are many people that have had experiences that align with panpsychism

It's not necessarily something that you have to believe, like a made-up story. Instead, it's something that you can experience for yourself (either through yoga, meditation, breathing, psychedelics or other forms of attaining different states of consciousness)

Edit: (can't reply to the reply) @tsimionescu it seems you just want to contradict whatever I say, that's your personal opinion. If you want a reason, you can come up with a thousand different ones. I'm not trying to convince anyone of anything, just offering a point of view for a, hopefully interesting, conversation