"Many tarantula species will frequently kick hairs off their abdomens, directing them toward potential attackers. These hairs can embed themselves in the other animal's skin or eyes, thus inducing physical irritation."
Yeah, the itch a lot, too. I used to have a rose hair tarantula. Their bite stings a whole bunch but unless you're allergic it won't cause any real damage. Most tarantulas are pretty docile, like the Mexican Red Knee here, but I had a cobalt blue baboon tarantula straight up pounce on me while I was trying to feed it once. Scared the shit out of me.
I totally get this guy's reaction. A college friend had a huge phobia of frogs and any time we tried to show him one he'd do all of this "calm fear" thing but threw in a few "fuck you guys, get this thing away from me"