I worked for a place like this. Regular firings, sometimes every month. The CEO (who also self-funded the company) believed that regularly letting people go was a way of eliminating bad apples and forcing people to work harder and smarter. Similar to Netflix philosopy, but on a smaller scale.
Firings happened for all the reasons you'd think--politics, cliques, not being a "cultural fit." "Not being a team player" was often code for not trying hard enough to make your lead look good.
It was toxic and led to massive tech debt accumulation, as a succession of engineering managers all made new and different decisions on frameworks and technologies as soon as they were hired. Very little institutional knowledge.
Implicit quotas for regularly letting people go is just an insane way to run a business.
(edit: clarity)