It's not easy to learn by playing against computers, because they don't play like humans.
Being slaughtered by a strong human player is usually much more educational. You can usually transfer something from your opponent's play into yours, while you can't hope to transfer much from your computer opponent (unless you're already a super-strong GM).
Today I saw the weekly "I played a cheater" thread.
Is it really that a big a deal if you find out you played a cheater?
Even if you played a computer, which is actually what you are doing when you play a cheater, have you not had the opportunity to learn something and grow as a chess player? And, can't you feel like the bigger man because you played fairly?
Can't we all understand and agree that most cheaters eventually fail in life? and that those of us who don't have the potential to grow and succeed?