That is a much better description than practically every other take I have seen on this issue. The legal issue is not about removing access, pulling the rug, or changing policy. It is all about the intention and making public statements.

If they wanted to legally stop WPE from accessing their servers then adding a policy to the effect of limiting how much traffic a single company is allowed to do without a explicit contract would do that. Many companies has similar conditions added to their TOS at some point after an unconditional free-for-all. They might want to allow small companies to continue use their service for free, but start demanding payment from large companies who can afford to pay and who also have real impact on server and network costs. They don't explicitly write who those large companies are.