Exporting the J-10 to Pakistan? Is it official or just fanboy stuff?
The proposal of J-10 sales to Pakistan have been made twice. Once was in 2006, when the former President of Pakistan - General Pervaiz Musharraf was on a State-Visit and was given a tour of the CAC production plant for the J-10 combat aircraft. And the second instance was on an official visit by Chief of General Staff - Lieutenant General Waheed Arshad (Pakistan Army), to China, back in 2013.
And China has never exported anything that they themselves deploy in large quantity, especially when that equipment is still new and is still the pride of China's fighter development industry.
500 plus F-7s were/are in People's Liberation Army Air Force's inventory. Pakistan Air Force bought and operates close to 150 of them in it's combat aircraft fleet. Pre-1995, the People's Liberation Army Air Force had operated a large number of J-6s. Pakistan at one point in time, operated over 250 of those fighters. So your statement about China not selling fighters to Pakistan, which itself operated in large numbers, is not true.
The thing is, many have underestimated or doubted Pakistan's friendship and alliance with China, and have failed miserably at accurately defining the alliance. Pakistan has a lot of honor for China, both as a close friend and as it's primary ally. So I would not doubt for a moment, that if China concludes that a sale of J-10s to Pakistan is permissible. Then you can be darn sure that it is, a matter of fact and cannot be debunked.
It is another matter though, despite the fact that China is our very close friend and ally. That if Pakistan knows that it cannot justify buying J-10s, either financially, operationally or both. Then Pakistan would say so and appreciatively, be forthcoming to China for those reasons. And that is one of the reasons which have been stated by Pakistan Military in the past. In particular, due to the corrupt former Zardari-Government, which wrecked and nearly destroyed Pakistan's economy.
And yes, I agree with your statement, that China has every justifiable reason not to sell J-10 to anyone. It is after all, a Chinese combat aircraft and they have every right to choose not to sell to whom so ever they want. The J-10 is, in no uncertain terms, an fine combat aircraft and quite an achievement by China.