It's a free country. They can sell for whatever the market will bear. They make a reasonable profit at MSRP, and most dealers do that. But a few are sleazeballs.
If a dealer has a list, and a contractual agreement (written or verbal) to sell to the people on the list in the order they signed on, at a specified price, he is legally required to fulfill that contract. But if a dealer chooses not to use a list, selling instead to whoever he likes, or if a dealer has not quoted a price to the people on his list, then he is under no legal obligation.
However, you can inform Toyota if you know of a dealer who charges over MSRP, and hope that maybe they will allocate him fewer cars, sending them instead to dealers who charge MSRP.