I doubt it the bitcoin devs are working for free. And a healthy competition is always a good thing even though the Core team has been a little bit too self-absorbed.
Most of them are. This is how open-source works. Some are employed by various entities.
Brian Armstrong went pretty hard on the Core developers and their opinions on the block size.
It is a systemic threat because he can't push his own agenda. He's just wasting more time. This does not help anyone.