(Or, the other players really aren't stupid)
Pre-Flop Raising
In a loose fixed-limit game, the reason for raising matters. With a strong hand, raise for value when weaker hands will call. With a speculative hand, prefer a cheap multiway entry. Do not apply a blanket rule to avoid all preflop raises: concealing strength does not usually compensate for passing up a clear value edge.
For example, a suited ace such as the following can be a useful multiway hand at the right price:
Calling one bet in position after several limpers can be reasonable if more raises are unlikely. Calling several bets cold is a different investment. A raise after you have already called costs one additional bet if no one re-raises; evaluate that price against the pot and the raiser's range. Going from $3 to $6 or $12 changes more than variance: it changes your cost, possible ranges, future betting and whether the call is worthwhile.
A nut-flush draw can perform well against many callers, but you still need the right pot odds and a plan for later streets. A single pair with a weak kicker can be dominated. Do not keep entering more pots merely because your cards are suited.
Raising Can Be Contagious
Take a typical 3-6 Hold 'em game where six or seven people are seeing the flop every single hand. Add to that game one tight and aggressive pre-flop raiser, let's say someone following Abdul Jalib's low limit advice (which is very good advice) and raising pre-flop with A-Q offsuit etc. You can usually count on a lot of action on the table if someone comes in and starts raising hands. The "gamblers" will start re-raising with any suited connector, and pretty soon you have a situation where pots are being capped before the flop.
If raising regularly triggers re-raises, tighten the speculative part of your range and budget for the likely total price. You cannot reliably control a table's future aggression by limping. Continue to take clear value raises with your strongest hands; do not build big pots with marginal hands just to provoke action.
If fewer players are seeing the flop, adjust the chart to the actual game. A hand that depends on cheap multiway action may be a poor cold-call against two opponents and a tight raiser.
Raising Gives Information
If you raise pre-flop with only AQ, AK, AA, KK and QQ then you are giving your opponents a huge amount of information. Have you seen the following scenario at a low limit table? Player 1 raises pre-flop, Player 2 calls. Flop is garbage Player 1 bets, Player 2 calls, Turn is garbage--Player 1 bets, Player 2 calls. River is garbage, Player 1 bets, Player 2 raises, Player 1 calls and Player 2 shows off 2 pairs of garbage.
Player 2 was able to accurately put player 1 on a large pair (QQ, KK or AA) and used that information to extract an extra bet from them on the river when they picked up a 2 to go with their 7 (for example).
Observant opponents can learn from a narrow raising range. That is a reason to pay attention to their reactions, not a reason to give up profitable raises or add random weak hands. Many low-limit opponents will still call your strong hands too often. Respond to the board and betting rather than assuming your preflop raise entitles you to win.
Match the raise to its purpose
Raise for value when weaker ranges will pay. Attempt isolation when players behind are likely to fold. Call speculatively when the multiway price, position and potential payoff fit; fold when they do not.