Over half the entire population out demonstrating is not the radicals taking over, but there's bound to be a few easily found to spin up any desired message, amongst millions.
What matters is they're too radical for the current CCP leadership. It doesn't matter that the agreement provides mutually agreed and signed written promise of universal suffrage in election of the Chief Executive, and I think of the Legislative Council.
Which is a slap in the face for HKers with every Chief Exec appointee from Beijing with the comical farce of the "show election". Surprise, Beijing's choice wins every election!
Had Hu not been forced to resign and publicly recant, Tiananmen and the China wide protests might have gone very differently. The hopes and optimism expressed in the article had a real chance of becoming true. Being forced out for not being harsh enough on protesters, months before Tiananmen and only weeks into the demonstrations changed everything both in China, and for Hong Kong's future.