Caravan Discrimination

Have you asked the respective site owners? We can only guess at their reasons which might be issues such as narrow approach roads and difficult access.

I've also seen sites that exclude motorhomes due to ground conditions. They're individually run so they can set their own rules.

It's not like it's an epidemic. There are still plenty to choose from.

How wide spread have you found it? There are always a minority of CL's that have different restrictions. Some don't take dogs because of the proximity of livestock. Some don't accept children because there is unprotected open water on the CL. As Wherenext points out some might exclude motorhomes because the ground is either too sloping or unstable. If a CL excludes caravans (and such CL's must be in a tiny minority) there will be reasons, perhaps towed access or other reasons? 

David 

CL owners are pretty much free agents and so they should be, make decisions, I'm sure, in the best interests of their sites and those who visit. Such restrictions are few and far between in my experience and where found are in place for good reason.