That's just one of those oversimplified Internet myths that like most myths is pretty bad advice.
It's more helpful to remember two other EQ "truisms":
1. "Use EQ cut to make things sound better, use EQ boost to make things sound different." What this really means is EQ is mostly used to make things sound better by removing bad-sounding attributes, whereas boosting does nothing to remove the bad, but rather changes the nature of the good the bad and the ugly.
2. "Cut narrow and deep, boost wide and shallow". In other words, the "bad" frequencies one usually wants to cut are usually limited bandwidth "spots" that you want to attack with fairly deep and surgically narrow cuts, whereas boosts are usually wider and more gradual fine-tuning "bumps" to shape the overall sound, and not targeted surgical attacks.
None of these "truisms" are hard-and-fast rules, there are always exceptions somewhere along the line, but they in general tend to apply more often than they don't.
If you really want what you're looking for, just do a search for the phrase "linear phase EQ", as those take care of the specific potential issue you're asking about. But there are plenty of perfectly fine EQs that are not linear phase that you can use to boost frequencies just fine as long as you use the EQ properly.
G.