The funny thing about all of this "Mercedes was hit on purpose!!" is that other teams fans claimed the same when there were rules changes that affected then.
The facts are that basically all rule changes of the last 5 years were of more universal impact and weren't meant to privilege any team.
2017 overhaul? Everyone had to change and the new rules didn't hit Mercedes core aero strengths (you could even argue the new rules were a good thing for Mercedes, despite Ferrari getting close to them).
Limited oil burning? Ferrari was the most affected by it, and basically had an engine banned because of it.
Front wing change? All top teams were hurt by it. Midfield teams were benefited by the simplicity. One could make the argument that high rake cars took the largest hit, but I am not certain about it.
Pirelli changing their tires? Most of the times the changes worked for Mercedes or were neutral.
FRIC ban? Red Bull and Renault were also affected by it.
Quali mode ban? Yes, it hurt Mercedes, but didn't take away their dominance.
DAS was banned for 2021 even before it debuted, ironically.
This year's ruled changes weren't ment to be a big deal and everyone thought the grid would be stagnant. By surprise Red Bull nailed their concept and Mercedes messed up a little bit. Bad luck for the silver arrows, it happens.
If you want to blame anyone, blame Adrian Newey.
PS: Hamilton saying that the changes were "aimed at slowing down Mercedes" is a classic mindgame.