In general, it seems to make sense to have different taxes for items with substantially-different negative externalities, e.g. a carbon tax or cigarette tax.

It shouldn't - their are good uses too. Their dream is an example of throwing the baby out with the bathwater.

I'm not answering for hirundo as I suspect our views are different.

But generally speaking it has been recognized that broad based sales taxes across all products is more stable when it comes to various economic downturns and etc. Same goes for just say property taxes that cover X, but not Y property.

Some sin taxes that get tagged to be used for "good things" often have bad results if usage drops and the "good things" that we previously wanted to fun suddenly have no (or a dramatic drop) in funding.

I'm not saying anyone shouldn't / can't do such things but there are reasons to avoid tax policies where things are taxes dramatically differently. How much "dramatically" is obviously up for endless debate.

That doesn't mean "tax should be the same for all items" but keeping close to that concept is not a bad idea.

That’s more of an argument for not using sin taxes to fund anything other than public health measures to combat the effects of consuming the thing that’s being taxed.

It is but it demonstrates why you want a more even tax base just to help ride out any changes in economics or usage.

Also even direct sin taxes tied to things might be hard. If we all stop smoking, there still be cancer related to smoking...

Gas tax to fund roads, and increased fuel efficiency is another example.