Can you help be more specific on which part you disagree with? The first part or the second part of his statement? Or both?
Thanks!
. . . erm - sorry, I'm a vague kind of a guy!
If you use IR cut filters on lenses wider than around 35mm then you are likely to get colour shifts in the corners. Also off balance colours.
if you use IR cut filters on lenses longer than around 35mm then you won't get colour shifts - but IMHO you will get slightly off balance colours.
As for using UV filters on wider lenses . . . Leica spend lots of effort on making their multi-coating perfect for the lens, if you add another lens with different multi-coating on the front, then you aren't going to be making the best of your lenses . . . of course, some people will disagree with this, but to my mind it stands to reason that it's best not to use filters unless you have to (i.e. with the M8).
Easier to simply not use them!
P.S. sod's law suggests that having said this I will now go and scratch one of my front elements