[Meta] Rude player?

Hi, I had trouble coming up with a title, sorry.

So I met 2 people in an RPG chatroom and we decided to start a game in the near future. We've moved to a separate chatroom to start preparing. This chatroom had been previously used by another player on a similar campaign, but was empty.

Soon after, another persons joins the chat. Reading the chat history, they appear to have been the GM for that previous campaign. I waved at their entry, making my presence known. This was their only text message:

Hi ​_<chatroom owner>_. Good to see you back in the game. I'm interested in playing but I'll let you know straight off; I can only play on <schedule>. Is that okay for your other players?

This isn't sitting right with me.

• No introduction.
• Talking about me like I'm not there.
• A certain attitude in setting terms to a game they're not organizing.
• The person they're talking to can't answer the question, and I wasn't addressed, so what now?

Am I reading too much into this? Is this just they trying to communicate efficiently plus a lack of social polish?

Anyway, I'd love some external perspective.

Edit: thanks everyone, I'm glad I took the time to gather your input. I wasn't sure I was reading the situation correctly and it looks like indeed I wasn't.