True that most nations exporting military equipment especially high-end technologies like fighters and bombers, would use it to leverage their political interests. I don't think anyway is calling Russia out for that, just stating facts that independence needs to happen for China and it needed to start somewhere, with or without short-term pains, losses, and costs in time. China adapting the flanker platform is no different to China adapting the Mig-21. Completely taking apart Russian versions and kits and evaluating then correcting flaws that were purposefully built into it. China had the ability to create their copies of flankers. Of course they would take that path. Other nations capable of this copying feat have done so in the past. Domesticating the flanker has helped China immensely and if it is/was at the cost of Russian favour, it has been paid back in many other ways and Russia still continues to find favour and support from China on multiple fronts. I don't think Russians can reasonably be bitter over the sino-flanker fiasco. They've even purchased Su-30MK2s and Su-35s (but of course that's all just to continue copying upgraded flankers... totally not for good-will at all). I don't recall brits being vocal about soviets copying the Rolls Royce RB.41.
Russo-Sino cooperation on these fronts would have only slowed China's domestic development down. Maybe at the cost of getting better equipment faster but so many industries would not have enjoyed the financing and encouragement they did without this cooperation and today there are certain areas where China at least matches the technical abilities of Russia and the trends show China's MIC will eventually be more successful than Russia's. Chinese intentions have always been establishing some sort of self reliance. If one day in the future, the Russian nation completely recovers from the damages done on it in the 20th century (and current US actions) and re-establishes its MIC dominance, China will likely return as an investor and customer for Russian products not available from Chinese MIC. At least until the product is reverse-engineered