There have already been many SCOTUS cases that say you are wrong. There are also many cases where people have been illegally detained, which is what a stop and frisk is, that have filed lawsuits themselves and have won thousands of dollars. That is one thing that is not covered by qualified immunity. When you're a hammer everything looks like a nail. When you're a pig everyone looks like a criminal. Pigs have the same RIGHTS as every other citizen but some reason the think they have rights above and beyond that. Pigs do not have the RIGHT or authority to violate a citizen's civil right and it has been determined by SCOTUS that Stop and Frisk is a 4th amendment violation. And yes there have been many cases thrown out and victims of over zealous pigs awarded thousands of dollars in lawsuits because they didn't have legimate probable cause for an arrest. The biggest problem with that is that the individual pigs are not held accountable by their superiors that condone the illegal behavior and the lawsuits are settled with taxpayer money. Until Pigs that are sworn to uphold the law and the Constitution are held individually liable for breaking the law and violating their oath nothing will change. It's bad enough as it is now and what Trump is talking about will make a police state much worse. Pigs in general are cowards and most of them don't deserve to have the jobs they do.
Like I said, there is a big gulf between what a cop can get away with as a practical matter, and what they are supposed to do as a matter of technical legal theory.
Some people might like to think that all legal proceedings are handled as full-on law school discussions, with all the legal precepts discussed in full, and the legal conclusions drawn therefrom conscientiously applied. That isn't how it works in the real world.
Articulable suspicion and probable cause, for example, really only matter once you get to an appellate hearing, and to do that, you have to go through the entire process of an arrest, an arraignment, and a trial first. You have to make a motion at or before trial to exclude evidence that you believe was unconstitutionally obtained, and if the judge rules against you, then you have to complete the entire trial before you get to raise the issue. Some trial judges will consider the issue carefully, particularly if it is a high-profile case; but if it's just an ordinary run-of-the-mill case, then the trial judge is most likely going to simply deny the defense motion and let the case proceed to trial. There are two reasons for this: (1) from the judge's perspective, it's a time-saving technique - if the judge grants the defense motion and dismisses the case, and that grant is overturned on appeal by the government, then everything has to be done all over again to prepare for trial; if the judge simply denies the defense motion and goes ahead and completes the trial that has already been prepared for, then there's an economy of time, and if the denial is reversed on appeal, and the case sent back for further proceedings, then all the judge has to do is to dismiss the case; on the other hand, if the appeal is denied, then that's the end of the matter and, again, the trial judge doesn't need to do anything further. (2) many criminal trial judges are ex-cops or ex-LEO themselves, or otherwise got into the business because they wanted to have justice done, and they are often inclined to rule against the defendant as a matter of course whenever the matter is subject to the judge's discretion.
So, as I said at the beginning, articulable suspicion and probable cause really only matter if a defendant has the ability to go through a trial and get to an appeals court.
That's reality, Jack, whether we like it or not.