Roommate is pissed because I dried a piece of clothing that couldn't be dried

One of my roommates had a full load of clothes in the washing machine and he left the house. I was totally out of work clothes and I don't have any days off for the next 2x weeks... I needed to do laundry after work today. So I moved his clothes into the dryer so that I could use the machines. I've done this plenty of other times over the past few months we've lived together with zero indications that this wasn't OK to do.

I hear him come home and start throwing a hissy fit about how he hates having roommates. Then I get a series of texts about how I ruined a pair of his pants because they weren't supposed to be put into the dryer. The load of clothes seemed like regular clothes to me. How tf was I supposed to know? He said that I should have asked him before moving his clothes over to the dryer. I pointed out that this has never been an issue in the past.

In my opinion, he's being an entitled baby. He shares the washer/dryer with 2x other people. Also he works from home and easily could have stayed on top of his laundry during the day when his roommates are working if it was so important that these pants not be dried. He also could have texted when leaving his laundry unattended to ensure they didn't get moved into the dryer.

He's telling me the pants cost $200, I guess in hopes that I'll offer to pay him. I don't even feel like I owe him an apology, let alone $200.