I am growing tired of this ...

If you wanted to take the count to an extreme you could just count individual Protestants and say there are that many denominations. Many Protestants today hold as I used to hold that there is no church that has got it all right so the primacy of ones interpretation of Scripture was supreme. In essence that would make ME a denomination if you are considering minutia in differentiation. In reality though my beliefs were pretty much in line with many other people I knew or read.

Quite frankly I think 30k is an overstating the case somewhat in terms of what I would consider core beliefs. So many of those differently labeled churches hold nearly identical core beliefs. The diversity of "non-negotiable" doctrines outside the Catholic Church can well be demonstrated without resorting to numbers which, to me, are truly difficult to accurately quantify. If you limited yourself to demonstrating 10 differences in belief on baptism alone you would get the point across far more effectively and without denigrating your opponents position to that of mere fancy.

Resume ...