The problem, they said, is that it would cause other tablet manufacturers to rethink their product design for fear of being sued by Apple for using such a common form factor.
But Apple's patent isn't as absurd as it sounds. In fact, it's very common for companies to patent their iconic product designs.
Coca-Cola has a patent for its Coke bottle, for example. And Ray Ban has a patent for its Wayfarer sunglasses.
Does that mean other soda companies can't put drinks in a glass bottle? Does that mean other eyewear companies can't make sunglasses with pointed tips at the top of the lenses?
And it doesn't mean other tablet manufacturers can't make tablets with rounded corners for fear of being sued out the nose by Apple.
Apple's newly-minted design patent will only protect it from blatant copies, according to Florian Mueller, who runs the popular patent blog Foss Patents.
"Apple could allege infringement by anyone who makes tablets with four evenly-rounded corners, but the validity of this patent is very questionable," Mueller said in an email interview. "It proved difficult enough for Apple to defend a design patent that covered a particular combination of multiple characteristics, so it's hard to imagine that this broad and general design patent will be deemed valid by the courts."
On the other hand, Mueller called it "regrettable" that the U.S. Patent and Trademark Office would award the design patent to Apple in a time when the tech industry is especially sensitive to the problems over broad patents can cause.