So if you cripple ripgrep, to act like grep, it is not much faster. This is kind of obvious. Ripgrep is faster because it makes assumptions, that will hold true for a large part of its users.

This is like saying "if I remove wings from a plane, then it won't go much faster than my car. So a plane is not technically faster than a car"

Of course, users should know the difference between grep and ripgrep (especially with tweaks like .gitignore, which could be confusing if you don't know).