Well, the key is “what kind of taxes, and on what?”
Taxes that distort incentives away from the no-externality, no-taxes perfect competition equilibrium, do create econ-101-style inefficiency, but not all possible taxes distort incentives, not all possible taxes are on things that have no negative externalities, and not all markets are in a perfect competition equilibrium.
Well, the key is “what kind of taxes, and on what?”
Taxes that distort incentives away from the no-externality, no-taxes perfect competition equilibrium, do create econ-101-style inefficiency, but not all possible taxes distort incentives, not all possible taxes are on things that have no negative externalities, and not all markets are in a perfect competition equilibrium.
In the real world, all else is never equal.