Yup. Except they flicker at double the mains frequency because they use both the positive and negative half-cycle thanks to a FULL BRIDGE RECTIFIER.

And see my other comment: it's not unhealthy, just annoying. To be honest, I use trash-picked LED bulbs and repair them, and I don't normally care to replace a poor smoothing capacitor. In rooms I spend much of my time, I make sure most bulbs in the fixture are low-flicker (it's arbitrary but generally don't get below 75%) for comfort. I'm not peculiar about light quality like CRI and matching color temperature unless it's very obviously bad, although I do notice the circadian effects of cold white light. I do mark badly flickering bulbs though so I know not to put too many of them together unless it's somewhere non-consequential like a cellar. I also hold my phone camera to any neutral-white E27s I salvage to find and mark true flicker-free ones because I use them while filming.