Good point, everyone should stop paying taxes immediately!

Since this configurable option only creates downsides from changing its default, why should it exist in the first place?

No, that's appeal to popularity fallacy. Let's say some non-trivial segment of users say their unlucky number is 13. Does that mean Bitcoin Core should support a configuration to censor transactions that contain the number 13 in them?

Mara is still mining transactions below 1 sat/vbyte. They just aren't mining bids as low as 0.1 sat/vbyte, it appears their price floor is 0.5 sat/vbyte.

The bet is that your fork will gain more adoption than Bitcoin Core. ...you ARE planning on forking, right?