"I agree" is presumably shorthand for "I agree to the linked license", or in other words "I agree to the GPL3", or to expand that, "I agree that I am not requir

"I agree" is presumably shorthand for "I agree to the linked license", or in other words "I agree to the GPL3", or to expand that, "I agree that I am not required to accept this License in order to receive or run a copy of the Program". Since that's part of the GPL3 text. So I wouldn't worry about it.