Plastic bags and papers straws is not about CO2 emissions and I wish people would stop repeating this like it's some "gotcha", it's about landfill and natural area pollution and damage to wildlife and natural areas, and that's how it's always been talked about by policy people who have advocated on this stuff.
This makes sense and I'm with you, people that are polluting beaches and natural areas should face harder punishments. That being said I'm missing plastic straws for drinking cold coffee.
Nothing stopping you from carrying your own reusable straw around with you.
Finally, most of the (local, not even thinking about the developing world) pollution is not deliberate. It blows in from other places, usually. I live rural and I'm continually picking up plastic garbage from my ditch or back forest or fields that blows in from the nearby highway and roads, especially after garbage pickup day.
Rituals define a school of thought (or a religion). These are rituals of folks who want to prevent catastrophe through conservation. To each their own.
Ultimately, individual habits do add up. But with climate, one would be hard pressed to find evidence that conservation is the path forward. It does not work, unfortunately.
Plastic bags, paper straws (wrapped in plastic), most realities of recycling, vehicle selections, etc.
Leads to a lot of unpopular things.