"Yes, I'm late on my payments, but it's not as bad as those that don't pay at all, so you shouldn't treat me badly, as you should with those that don't pay at all, so back the hell up off me." Somehow, because the late payer is paying whereas the non-payer isn't, the payer feels justified in what they're doing since what others do is worst.
Is this a good example?
ETA: I shouldn't say, "badly". We shouldn't treat slow payers nor non-payers badly, but they should both be held accountable for their failure to make timely payments. Thus, we should 'explain' to slow payers the importance of not paying late. The fact that slow paying customers at least pay when non-payers don't pay does not mitigate their responsibility, so their "not as bad argument" doesn't hold weight.
That would be like a boy touching a girls boobs saying he shouldn't get in trouble because his actions aren't as bad as people who rape.