China purchased a specific number of Su-27s (200) to be constructed in-country using Russian-supplied kits. The Russians did NOT give permission for China to copy (and subsequently modify) the design and thereafter produce several hundred more using local subsystems, so let's not get dishonest about the conditions of the original deal here. The F-2 was a fully authorized licensed production deal between Japan and the US split 60/40, nothing even remotely similar to how China 'acquired' and indigenized the Su-27 design. The IAI Nesher, however, is VERY similar to the Chinese Su-27 in that Israel commenced development and production even after France canned the project, with Dassault secretly supplying IAI some subsystems behind the government's back.
It still galls me every time I read crap like this on SDF and the various ways fanbois here twist and spindoctor the blatant technology theft that resulted in the J-11B. Is it shame that there was blatant theft that leads to these surreal statements? Countries steal from each other all the time; there is no need for intellectual dishonesty here.
You and AssassinsMace are both correct in your own ways. You've ignored the point he's trying to make. That being, China took out what they didn't like in the Su-27 design and added what they wanted to add, in this case it was domestic subsystems and ability to completely use Chinese weapons. So his point is, the charge that China copied the Su-27 entirely isn't accurate since all the innards and subsystems are Chinese not Russian. In fact the whole point of the domesticising exercise to make the Su-27 into the J-11 was to NOT copy the subsystems that made the fighter thoroughly Russian. The Russian Su-27 exported in built form and kits did not have an ability to fire Chinese weapons or become compatible with Chinese avionics and radar. Even the positioning of the IRST is different along with the system itself on the J-11B. It's a flanker derivative and PLAAF has stuck with the flanker design because it offers range and payload along with many attributes that were never available to PLAAF in the past. It's still building off this platform today because it's a damn good platform for subsurface upgrades just like the Russians have been doing.
But you are correct in the direction you're coming from. That being the J-11 is a outward copy of the Su-27 and engineered from the kits supplied. The thing is no one here denies that or wants to hide it. There is not evidence anyone wants to hide that fact. What AM was challenging was the half-arsed conclusion that the J-11 is a Su-27 copy. If the avionics, electronics, and software are totally Chinese origin and not copies of what was onboard Su-27, then it's better to not be extreme in either view. I think his main point is criticising the article in the assumption it makes that everything Chinese must be derived from a foreign design... in this case it was the D-21 allegation.
It's Cypher's post that alluded to the kit assembly deal. He asked a question. He's been corrected. It's not a forum fanboy thing like you're claiming. One guy asked a question whether kit assembly and modification counts as stealing. This question is a difficult to answer one but interesting. Personally I consider it as a violation of Sukhoi's IP and faith that engineers at SAC who could reverse engineer and build the entire thing, wouldn't do just that. 90s China didn't care for respecting this and valued producing unlimited numbers of their own domesticised flankers as more important than respecting Sukhoi's IP. The decision was a pragmatic and financial one. It has less to do with technology and capability. Of course China back then wasn't wealthy enough to devote decades into developing their own F-15/ Su-27 equivalent even if it had the ability and organisation to do so. The need was for hundreds of these heavy fighters. The price in this case was reputation and goodwill from the Russians.