Not in the slightest, and I have no idea where this idea even came from. Whatever amount of stress the engine and rest of the drivetrain is under even at maximum engine braking, it experiences significantly more under any hard acceleration. Even semi truck jake brakes that actually reconfigure the engine's air flow to generate even more deceleration forces than would otherwise be possible max out at a fraction of the acceleration powers that same engine is capable of producing.
The only part of a standard automotive drivetrain that has significant directional differences in strength/wear would be the differential gears, but even that difference isn't going to matter in anything close to normal use. If you're doing clutch drops in reverse that's another matter.
The biggest risk to anything drivetrain-related from engine braking would be badly shifting a manual transmission and either damaging the transmission itself or choosing the wrong gear and over-revving the engine.
The brake light thing I fully agree with you though. I love engine braking when I'm doing performance driving as much as the next guy, but I won't do it in traffic for anything more than holding speed on a downhill for that reason. Significant deceleration in traffic should always be accompanied by brake lights.