In many countries, taxis are often specifically exempted from child seat mandates. Doesn't make them any safer, but it's not necessarily illegal.

I've taken taxis with infants and small children several dozen times. It doesn't take me more than about twenty seconds to pop the car seat out of the stroller and latch it into the back seat of a taxi, for slightly older kids we have a few lightweight folding booster seats, and personally I've found that a car seat vest is particularly handy and lightweight.

A quick search online shows that your statement is misinformation, taxis can be exempted in many "western" countries.

Before making such bold claims, you've got to know a little tiny bit of the topic or at least look it up to make sure.