I dont know what kind of games he plays in, but in fairly tight-aggressive online games you raise preflop with a pretty good chance of comming away with either the blinds, or the blinds and a cbet. Limping on the other hand will usually face an isolation raise from a wide enough range that calling hands like low PPs, SCs and looking to hit flops is not going to get the implied odds it needs to be profitable. The protection to this would be limping hands like AA occasionally but thats going to cause you to lose value against the 1 or 2 loose fish at the table, and sometimes leave you with a 4 way limped pot where you have no idea where you are.

In loose passive games I can see a case for limping most speculative hands from early position, but in most online games I think the "standard TAG" way of playing these hands is going to be much more profitable.

I think the more interesting part of that section is that he advocates raising 3x with 1 pair type hands like AK, and 4x with speculative nut hands like sethunting pairs. Assuming table conditions are right that 3x will usually only get 1-2 callers preflop, Id be interested to hear what other people had to say on this, especially with relatively deep stacks (say 150bb+).