Cambridge orders coronavirus-related ban on reusable bags at stores, lifts 10-cent fee for store bags

While I agree with your second point about less packaging, I think that reusable bags should remain the defacto norm here. If there is any issues with their use, it's only because the $0.15 fee for cheaper, plastic "re-usable" bags is too low and some people still single-use those. Stores need to have no cheap, purchasable bags that are not full on canvas. Tote bags are better for carrying groceries without breaking. Some of those studies try to compare the use rate vs production costs, but unless you have crappy bags that break, a set of tote bags will last you years or even decades. And the biggest benefit of all is that those plastic bags were often littered to the rate that on a windy day every tree in the neighborhood was full of bag fruit. I have definitely seen a huge decline in that type of litter.

Incidentally, in Boston Star Markets anyhow, they have a much more sensible policy on re-usable bags. You bring your own, like always. You bag your own groceries. Thus nobody else touches your bags. This makes the most sense, because even in healthier times the store clerks are incapable of bagging things in a sensible manner and you would end up with bread flattened under the milk or wildly unbalanced weight between bags.

There's a discussion of such studies here. It's not so clear as you claim, that the reusable effort "has backfired."

Though the studies looked at a number of environmental impacts, including greenhouse gas emissions from manufacturing, water use in producing materials and the toxicity of the production processes, some less easily quantifiable (but equally important) factors were left out — namely, damage to marine wildlife and ecosystems, for which plastic bags are notorious.

The impact of reusables is ultimately a function of how many times they are used. I have bags from TJ's that are over 10 years old, and have probably been used 100 times. In places like Hawaii, where disposables are banned, reusables probably reach that level of use routinely.

Unless after every use you put your reusable bag through a hot water and bleach washing cycle -- you are very likely to harbor micro organisms in the fabric

You saying it doesn't make it true. A normal laundering of cloth bags would certainly dispose of any COVID-19-causing virus, and likely a lot of bacteria as well. Even if you were correct, hot-water and bleach washing is not a major hurdle; all our laundering systems are capable of doing it.

...so adamant to ban one time sanitary, economical and actually not very polluting plastic...

Not very polluting? The things are a disaster for marine life. I had to get a long painter's pole and screw a hook into the end to pull somebody's plastic bag down out of our tree the other day. It had hung there for a week, wrapped around a branch, and because it was not biodegradable, it would likely have been there for months.

Paper is a reusable / recyclable / sustainable resource

Except its energy footprint is significantly greater than plastic.

The trouble with paper bags: carbon emissions

So does that mean paper bags, which degrade more easily, are a better option? Not necessarily. Climate change has become the biggest environmental issue of our time, so it’s worth looking at things from an emissions standpoint. And on that score, paper bags fare worse.

Even though paper bags are made from trees, which are, in theory, a renewable resource, it takes significantly more energy to create pulp and manufacture a paper bag than it does to make a single-use plastic bag from oil.

People making simplistic, judgemental claims should be banned.