WH,
I don't think people are specifically anti Stansted or the ATC there, it is just that getting zones transits are particularly difficult and that can be frustrating. I am sure that the same views are held about Luton, Manchester, Gatwick, Glasgow etc. These airports have seen a huge increase in heavy metal traffic over the last 10 years or so and maybe out grown their class D airspace. ATC have to maintain IFR seperation for departures and most arrivals (since most traffic will be on an IFR flight plan) so accommodating GA traffic transits cannot always be easy. The fact that there are so many recommendations to avoid Stansted is simply a reflection of the density of GA traffic in that area. If you are flying for fun (and therefore having to pay for it) these places are best avoided, if nothing else just to make your own flight easier.
With continued increased usage by commercial traffic and the continual issue of airspace infringements, there must come a time when these airports will try to claim Class A airspace. Perhaps a general GA policy of avoiding these places unless necessary would delay this.