Was he the CTO as well? That’s who should really be fired (unless Matze hired the CTO in which case sack them both).
Now imagine all of those services say "nah, you're done". All of the sudden you need to roll your own everything. You have millions of users and no access to fractional development of load balancing, crafting emails to avoid spam filter, best practices in 2FA, well organized chat permission systems. It's the true nightmare scenario for a modern company.
If you say "they should have anticipated being de-platformed", well they probably never would have made it as far if they had focused on that.