Link: https://nitter.net/TeamFortressS2/status/1745157814295617767
Valve is generally supportive of mods (hell, a Portal 2 mod was just released a few days ago) but it seems like recreating Team Fortress 2 was pushing it… Really sad, honestly. I really hope Valve would just strike a deal with these devs and make it official rather than throw away the insane amount of effort they put into re-building TF2.
If I had to guess a real reason why: a new TF game in Source 2, or something similar is in the works at Valve. It may never make it out of pre-production, but it wouldn’t surprise me.
It would surprise me if they did it to capitalize on Overwatch, which would show that Valve leadership can’t make an original idea, and is chasing an also-ran that’s not successful.