Get her to laugh and respond.
It was okay to message her because:
You can shave your beard at any time.
Maybe it's not actually the dealbreaker she thinks it is. It's extremely common in dating for people to misperceive their own deal-breakers, so there's no harm in trying when the maximum harm you can cause her is the burden of clicking "delete" on your message.
Her long rant contained unwarranted personal attacks. Basically, you're not the one who needs the advice here.
Further edit:
In no way were you disrespectful. You should have simply said "hmm, those lyrics are a pretty good start but I Expected a bit more I have to say. Reply to her:
"Except that I am pretty cool, so I'm still waiting for your lyrics, girl give me something that I Can work with.
If she is pissed off again, you can say the first line I wrote.