Well, the alternative is competing based on what you are actually selling in this model: Support for this product. If I can clone your distro and do better at supporting it than YOU do or at least good enough to sell my support, then you have a situation of possibilities:

• Your support sucks
• You're charging too much or don't have the right market / price options available
• Your support in general is not really necessary, and thus your business model is weak in the first place. Another way of saying this one is that you aren't offering anying particularly unique for new features on top of what's already freely available to sweeten the deal beyond selling support.
• You've done other things to your customers to weaken your relationships, and thus income flow

Locking out those "second run" vendors who are riding your coat tails is going to be a self-defeating path, however you slice it. Oracle has deep pockets - they are unlikely to sit back on this one as an example problem. The bigger problem is violation of the spirit of the GPL which alienates devs. You're correct that they may only be inconvenienced, but inconveniencing any developer is a first class ticket to them working around your shenanigans or just opting out of supporting your platform in general. I already know 2 vendors in my small world who are subtly indicating support for RHEL and CentOS is being considered with some pushes on their customers to consider other distros. That's in the last few days!

Anyway, they are throwing out the good will they have left with the bathwater of trying to short circuit low-bar competitors because they want to squeeze profit. You may not be wrong to stand by them, but I'm taking my support (and business) elsewhere as a result of their stance. A recent post looks like they are doubling down on the message.