The As-Is is merely a statement of the Seller's intent and not a binding agreement - as Bill said below.... "read it" and it is pretty clear. Your agent should have told you how this might play out.
When the Seller accepts the Buyer's property inspection contingency it gives them the right to cancel or try to renegotiate. Period end of story. The Seller can say "no" to any demands and cite the As-Is, but it wouldn't be the first time a Seller changed their mind about their "intent" to not negotiate. And the buyer using their contingency has every right to ask.
Also, stating that "all known defects" were disclosed is rather meaningless. First, there may be unknown defects. Second, a known defect may turn out to be far more expensive, or difficult, or time consuming than the buyers assumed when they're able to ask follow up questions of their own inspector or experts. Reading reports from experts is far, far different than seeing it first hand through the eyes of the inspection where you can ask follow up questions. Basically, "known defects" and actually "knowing" what they mean can be very, very different in the mind of buyers so getting ones own inspection often does provide new information.
This is basic stuff for experienced Realtors as you can see from all of the below comments from my colleagues.