Radar locks and jamming signals are problematic because they are how a real attack sequence would begin. And there is also no way to know the intention until the entire event happens. The US, especially, treats them as the real thing. So this is PLA taunting JSDF.
During the Cold War days, sure, but these days, the whole ballgame is about engaging opfor without them even knowing you are there until they get splashed. Not even some modern AAMs will give you the courtesy of a nice clear lock tone before impact.
The very fact you lived to get within WVR of opfor is already overwhelming evidence they are not trying to actually kill you.
In modern air positioning displays like this, a lock tone is purely messaging after a bout of dogfighting to tell the other guy you got them cold and that you are indisputably the superior pilot and/or have the superior plane. Only in the movies or if some literal cold warrior got teleported into the cockpit straight from the 1970s would the pilot genuinely think getting locked in such circumstances means they are seconds away from death.