Godaddy's position on this is against common law practice and I am not sure it would be defendable by them, if anyone took the case to court.
Basically, when someone issues a counteroffer, he effectively declines the offer and hence takes it off the table.
Stating something in TOS that is opposite of law should not make it legal.
"An offeree can conclude a bargain by accepting the offer he is given but only if his power of acceptance has not been terminated.
Termination of the offeree’s power of acceptance can result from any of the following six causes:
- expiration or lapse of the offer,
- rejection by the offeree,
- a counteroffer by the offeree,
- a qualified or conditional acceptance by the offeree,
- a valid revocation of the offer by the offeror, and
- by operation of law.
(3) A counteroffer by the offeree
The offeree’s power of acceptance can also be terminated by a counteroffer.
A counteroffer is an offer made by the offeree to the offeror that concerns the same subject matter as the original offer but differs in its terms. For example:
Picasso offers to paint Michelangelo’s house for $5,000. Michelangelo tells Picasso that he will pay $4,000. Michelangelo has given Picasso a counteroffer which terminates his power to accept Picasso’s original offer. Once Michelangelo has made his counteroffer, Picasso does not have to paint Michelangelo’s house if Michelangelo changes his mind and accepts Picasso’s original offer.
As we have just said, the legal effect of the counteroffer is that it terminates the offeree’s power of acceptance. However, the counteroffer is also an offer in and of itself and therefore, it creates a new power of acceptance in the original offeror. Note our example:
Picasso offers to paint Michelangelo’s house for $5,000. Michelangelo tells Picasso that he will pay $4,000. Michelangelo has given Picasso a counteroffer which terminates his power to accept Picasso’s original offer. However, the counteroffer is also an offer in and of itself so that Picasso can either accept Michelangelo’s offer to paint the house for $4,000 or he can reject the offer.
Please note that the offeree’s power of acceptance is not terminated by an inquiry concerning the offer or by a request for different terms. For example:
- Picasso offers to paint Michelangelo’s house for $5,000. Michelangelo asks Picasso if the price includes the cost of materials. This is not a counteroffer and Michelangelo is still free to accept Picasso’s offer.
- Picasso offers to paint Michelangelo’s house for $5,000. Michelangelo asks Picasso is there is any way he would do it for $4,000. This is not a counteroffer. This is simply a request for different terms and it does not terminate Michelangelo’s power to accept Picasso’s offer.
An option contract is a contract in which the offeror promises to keep his offer open for a certain amount of time and the offeree actually gives the offeror consideration for that promise (as opposed to our examples at the beginning of this chapter where no consideration is given for the promise to hold the offer open).
Where option contracts are involved, a counteroffer made during the option period does not terminate the power of acceptance because the offeree has the contractual right to have the offer held open during its term. See
Humble Oil and Refining Co., v. Westside Investment Corp., 428 S.W.2d 92 (Tex. 1968). For example:
Picasso offers to paint Michelangelo’s house for $5,000. Picasso agrees to keep the offer open for one month and, in exchange, Michelangelo gives Picasso $100 to keep the offer open for the month. In this situation, any counteroffer that Michelangelo makes during that month does not terminate his power of acceptance because he has the contractual right to have the offer held open for the entire month and thus, he has the contractual right to accept that offer for the entire month. "
https://lawshelf.com/courseware/entry/termination-of-the-power-of-acceptance