Trademark infringement using WordPress logo in Tshirt design?

https://wordpressfoundation.org/trademark-policy/

I can guarantee that if it was made with commercial intent, that would be a violation

What about non-commercial intent? Like making them just for people in my WordPress meetup?

Still a trademark infringement?

If I had to guess, by reading the link above, it sounds like they would like you to obtain permission – it also sounds like they would grant said permission

I would just contact them real quick with your intent – to be on the up-and-up!