They are exaggerating but not all wrong. As hiring manager my job is not to train you for your next job. I'm hiring for productivity and that takes time. If you are going to jump ship before you "pay" back the company then I'd rather skip on you. There is no test but I want 2-3 years if you take 9 months or more to get going and I'd be foolish if I didn't want more.

Lots of programmers think they are 10x but few are. Even my best senior engineers took 2-3 months to settle in and contribute more than they take and juniors are bigger gamble.

The best proxy now is will you spend 1 hour on a simple set of tests, if not you are not serious or are shopping for counteroffers.