I don't really see how it misleads the argument in a way that would be considered bad faith. But I do agree focusing on the $0 number does seem kind of arbitrary. A better metric might be percentage of the total tax burden paid by the bottom 50% of the income distribution. Maybe that is 0% if you look purely at federal income tax, and maybe it rises to something like 5% if you include all the other taxes you mention. But I don't think it changes the picture significantly.