This was a huge debate on USENET in particular, as well as in the email world until Outlook effectively made top posting the standard.

RFC 1855 [1] makes it clear that the correct way is to quote relevant text and then reply.

[1] https://datatracker.ietf.org/doc/html/rfc1855

It's been one of those "tabs vs spaces"-like holy wars for a while.

Consider yourself lucky. I’ve always adapted to the prevailing format of each mailing list, but the people who try to create a holy war out of different styles have always been insufferable.

In a normal office environment e-mail moves much faster, people open threads with the context already in mind, and expect to see the relevant new info at the top. Bottom posting would either make everyone sigh heavily when they see an e-mail from that one person or would earn someone a quick coaching session to adopt the prevailing style of the office environment.

But if you go on to a mailing list that wants bottom posting, that’s what you do. It’s a courtesy.