You obviously have no clue about air-to-air engagements. The strike lead was NOT DETECTED, which means Early Warning (EW) was not set off. That is the entire philosophy on which stealth aircraft technology is built. EW Radars hand off targets of interest to Target Tracking Radars (TTR) by sending bearing, range, and altitude information to the Radar crews. Then the target is prosecuted based upon their profile. Once within weapons range, the TTR illuminates the target with a Constant Wave (CW) Radar which reflects energy that is tracked by a guided missile, or a TTR sends tracking information to the missile via data link.
As an Electronics Counter-Measures Officer (ECMO), I have been embedded with strike groups and we used our jamming pods to deny EW Radars the ability to acquire targets and thus no hand-off to TTRs.
The entire point is to avoid EW detection. Once a TTR has a lock, stealth no longer applies.
The entire point of stealth is to not return enough energy to the EW or TTR radars for detection. As another data point, clearly the air-to-air radars carried by F-16s and F-18s (and from other sources, F-15s) aren't sufficient to detect either F-22s or F-35s (or for that matter, B-2s). Our stealth aircraft were built to successfully penetrate heavily defended airspace.
IR detection is another story, and I expect if the US can control the operational tempo most stealth missions will occur during overcast conditions. It is also true that only the F-22 and B-2 have all-aspect stealth, so F-35s may be detectable by radar during egress.