His source of information is internet, which hardly can be compared to a Flanker dedicated book. Now, even if Su33 couldn't deploy Moskit, it's still a cold, undeniable FACT, that this very book has more authority then some unnamed and hardly confirmed internet sources.
I agree with Veljko here: unless someone points to a valid source stating SU33 cannot carry Moskit, I'll belive Yephim Gordon who has, afterall, written 'few' pages on the matter.
And all those saying they haven't seen pictures of SU33 taking off with Moskit, think again: have you seen SU33 taking off with full AA load? No.
Does it mean it CAN'T take off with fuel AA load? Of course not. In the worst possible case scenario, it could take off with half the full and refuel when airborne (that's what the tankers and TOPAZ fuel tanks are for).