If possible, it's probably worth taking exchanges like this offline if you didn't in this case: speak to him either in person or on the phone (if you can't get a meeting). As you posted six days ago, I'm hoping it's already blown over. If so, leave it but do that if it happens again.
This was clearly an emotionally charged exchange – something that one-way communication methods like email or messaging systems are very bad for. It's so hard to convey nuance in email, partly because it's devoid of cues like facial expressions or intonation; and partly because it's slow and sequential (ie you write, they write, and so on). As a result, it tends to polarise exchanges and – where emotions are involved – drive people to eventually take extreme positions.
So many issues can be solved by a quick chat. He would have been better responding to you like that in the first place. (He was upset but responded by email – and now you're upset, which illustrates my point.) But you should be able to take the heat out of the situation (next time) by walking and talking.