That logic makes some sense to me... If the amps (or voltage or whatever) fluctuate wildly, it might be harder on your battery. But I don’t think the current does fluctuate wildly.

With a quick Google search, I wasn’t able to find much more than speculation on this point. Not really much hard evidence.

My understanding is that one reason USB charging from a computer is slow is precisely because the amperage is limited to prevent damage. The maximum current is already quite low. I’m sceptical there can be really wild fluctuations under these conditions. You couldn’t get a wild spike from a low to a very high current which would be the most damaging thing.

This is all my speculation, though.