Respectfully, I don't agree with you. You have pointed out the single biggest issue, which is that "commercial use" is being defined arbitrarily by Wyndham. Each party to a contract has an implied duty of good faith and fair dealing, and further, one of the rules of contract construction is that vague terms are construed against the drafter, particular with contracts of adhesion (i.e., contracts where the consumer has no say in the language of the contract).
Given that OP is simply passing his units on to friends and family members and recouping his MFs due to his inability to personally use what he owns, and not making a profit, I think Wyndham would have a very tough go of it, and they would be looking at 3 problems in a lawsuit: (1) whether a trial court might rule against them on the contract construction issue, which is likely, as Wyndham can't be arbitrary; (2) they would certainly be paying a lot of attorney's to fight the case; (3) if they lose, it would set a precedent that would be bad for them on a large scale, while if they were to agree to relent and allow this particular user to continue his practice, it would be considered an isolated "non-commercial use" that would have no impact on how they are treating other owners.
You might be surprised how frequently large companies make "business decisions" in this way, i.e., treating the masses poorly and settling the occasional legal challenge if it doesn't compromise their larger practice. Given that "commercial use" is decided on a case-by-case basis according to their whim, it would do them no harm to relent for this one person.
Wyndham's successful rationale is that almost everyone won't bother to challenge them, and in many cases, owners who did sue would not have the facts on their side because they are in fact engaging in commercial use for profit.
So I think your conclusion that Wyndham holds all the cards really isn't correct. What they do hold (as shown by your position) is the perception that they will win every legal challenge, the fact that almost every owner would not care to spend the money to challenge their application of "commercial use," and that in most cases, the facts are on their side, because a great many folks are in fact engaging in commercial use.
That said, I think virtually everyone who is not a lawyer would not find the investment of attorney's fees to be wise. Which Wyndham knows, and counts on.