State law always trumps seller policies. The seller can force you to check a box agreeing to their terms of sale but those terms are not enforceable if state law gives you other rights. Unenforceable clauses have been in literally every contract or terms of sale I've ever read.

Rightful rejection laws make sense too, especially when you start looking at large purchases. Let's say you ordered a black car from a dealer 500 miles away and the dealer delivered a pink one. The terms of sale say that you have to return the car to the dealer and pay a restocking fee for a refund. Those terms mean that the dealer has no obligation to deliver what you ordered or paid for and will make a profit (from you) even if they deliver something you didn't order. That's where Rightful Rejection laws become indispensable. All you have to do by law is make the product available for retrieval by the seller.

Funny you should mention Amazon - I'm literally dealing with this issue this week. They sent me a DOA item that has to be sent back. Amazon suddenly wants to charge me a fee to return a defective item that they have the legal obligation to retrieve. While I don't mind dropping things off at a UPS store because I'm regularly a block away, they want me to make a special trip to a Staples or Whole Foods which is not convenient or reasonable. I was just going to order a replacement from them, but because of their new return fee I won't be buying the replacement from Amazon, or much else going forward. My Amazon purchases will easily decrease by 90%.

Here's the rub - a retailer does not have to continue to do business with you. If you force Amazon to retrieve an item they can close your account and refuse to sell to you again.