True. China have a lot to thank Israel for selling to them cutting edge military technologies. Israel exported to China UAVs like the IAI Harpy loitering munition in the early 2000s. There are also other stuff like missiles, electronics, and radar tech sold by Israel to China. Its hard to find evidence about these deals now. But these were an open secret back in the early 2000s.
With all due credit to Chinese designers, it is not entirely impossible that the J-10 may have some inspiration or design inputs from the IAI Lavi program. The jets look outwardly similar, and they have similar roles, to be the single-engined multirole workhorses for their respected air forces.
I may be wrong, but I do suspect the Chinese HJ-10 and HJ-12 ATGMs may have benefited from some technology transfer from the Israeli Spike missiles. Other countries who developed similar systems needed to import Spike missiles beforehand. For example, South Korea and India imported the Spike missiles before developing their own systems. The Spike missile was submitted to participate in the US Army JAWS missile program in 1996, but then the US developed and selected the Javelin. I don't know if they reverse-engineered the Spike missile, but the Javelin looks and operates awfully similar. Russia has not yet developed a similar ATGM system till today. But then China, with no prior experience in developing modern F&F ATGMs, and had not bought such systems can suddenly come up with the HJ-10 and HJ-12? And they look and operate very similarly to Spike NLOS and Spike ER? I suspect there could be something going on in the background between Israel and China. Maybe legal, maybe not.
Even as recently as this year, some Israelis were caught secretly selling Israeli suicide drones (highly suspected to be IAI Harops) to China.
Now, don't get me wrong. Israel selling cutting edge military tech to China does not mean that they are suddenly the 'good guys'. It does not absolve Israel of the crimes against humanity that its inflicting onto the Palestinians in Gaza. This is not a problem for China to solve or condemn. China is in a grey zone here, but that has always been China's specialty in diplomacy. China has no problems getting along with Saudi Arabia, Myanmar, and various other despotic regimes. China just says, its not their business, and they don't interfere in the internal affairs of other countries. Because China is not a democracy, some Chinese citizens who hate Israel is not gonna affect Sino-Israeli ties.