Manager made up new rule that seems….ridiculous

I work remote on the east coast while my boss is on the west coast. I recently followed up on a pending message, which I have to do often because they leave me on “read” consistently.

When I followed up this time, they said they didn’t respond because they were waiting to hear back from me. I shared proof that I was actually the last person to reach out and was waiting on them.

Their response was that since I sent a message at the end of my day (which wasn’t true, it was 1.5 hours before end of day), that they will not respond and instead it is my responsibility to follow up the next day. Therefore, they were waiting on me.

I don’t understand this logic. Honestly just seems like an excuse to avoid accountability for not responding back and to avoid accountability in the future. They are west coast and still had half their day to respond. Why not just respond?!?!