Justaminute: It is understandable that when you have just 20 games allowance to play, the delay in moves gives you a harder time than when you have dozens, hundreds or thousands.
Instead of initiating a rivalry, it is best if you explain it to them and help them find games with better time-controls for their preferences.
As for the contribution, I was a non-paying member a few months back, as well.
Several of my games are against non-paying members because most paying members...do tend to move slowly for my liking, even in time-controls like 2dpm-no days off.
If people like the site, they can bring other members as well, which could either become paying members or contribute with their participation, ideas and, yes, even whining.
If paying members are being condescending instead of understanding and helpful, those people will, most likely, leave and the site loses with them leaving, as well.

Last, but not least, I think it is best to behave to non-paying members with the same respect you would want to be treated if you were a non-paying member.