My guy friend blocked me for calling him bro. What does that mean?

He told me if I called him bro again, he would block me. I called him bro and then he blocked me and I’ve been blocked for a day. This was over text. Why did he get annoyed at me for calling him bro? He told me he doesn’t like being called bro by me, and I asked why and he said because when he thinks about my boobs, and I call him bro, it doesn’t feel right. (wtf). Anyways, so I called him bro to piss him off because he’s disrespectful as I have a boyfriend and he knows that, yet he still continues to flirt.
My guy friend blocked me for calling him bro. What does that mean?
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