So the idea here is for China to do something that it thinks would rile the US galls and nothing else ? Gee, talk about a rather twisted example of cutting ones nose to spite the face.
For starters the J-31 is hardly the sole focus of US defense talks in the past decade, the Su-57 has garnered just as much talk of its potentials and export. It is just that the J-31 bears a greater similarity to the F-35 that makes it a better eye catcher in the headlines. If a few online articles suffice to justify a particular priority on an issue, I can bring forth a multitude of other topics that are just as gripping to the US's eye, namely : The Venezuelan crisis, the ongoing Iran war, the Syrian civil war, the Iskandar SRBM, the Yasen SSGN, North Korean ballistic missiles. All of which has a list of articles which are just as much, if not greater than the J-31 had commanded in the past.
Then there is the whole tortuous issue of making the J-31 marketable at a reasonable price tag. Considering how much effort has been put in to market the JF-17, one can imagine that in order for the J-31 to appear anymore appealing China would have to offer advance loans to the buying nation, hardly a recipe for commercial success in any stretch of the imagination. And then ticking off the list of nations who are by default wealthy enough to buy the J-31 and would not just as easily use the J-31 in mutual exercise with the US or any US affiliated nations and then automatically compromising its capabilities and you get a pretty merger selection to go by. And this is assuming, and that is a very BIG if, the final iteration of the J-31 would approach a level that would be considered an equal to the F-35 or the F-22 because in order for the J-31 to be successful, it has to present itself as a reasonably priced fighter
Moreover geopoliticaly a successful J-31 sale will have far less impact than, lets say a successful 5G contract sale. Heck, China can get just as much geopolitical and economical points by simply offering the multitude of 3 to 4 gen fighters it is developing alongside a healthy selection of air to ground munitions. A JH-7 armed with a AKG-400 AShM is a grave threat to any ship unless it has a full anti air suite.