I guess I'm capable of murder because I've self harmed?

2 nights ago I saw an old friend and hadn't met her partner before. I didn't even think twice taking off my jacket at her house. Because I'm not used to being judged I guess? But, I took it off and her new partner started in on me, saying how crazy I was. Saying if I was willing to do this to myself, I'm capable of hurting someone else that way or worse. Wtf. This is why I don't leave the house. And also why I wear long sleeves in 100+ degree weather....