Single-use anything can be a climate change problem (besides being an obvious pollution problem). Single-use means new onrs being constantly manufactured and used ones being constantly destroyed/recycled. All of those are energy intensive processes, not to mention the energy use for constantly getting more raw materials. More energy use means more GHG emissions.
Making plastic straws is not energy-intensive and the miniscule amount of electricity used can be trivially obtained from renewables.
You all are grasping at straws. Of all the things in the world to want to stop making from oil, plastic straws have got to be at the bottom right before medical supplies.
I'm not saying plastic straws are the problem, I'm saying single-use things are a problem. Straws, not matter the material, are just one tiny part of that.
And I'm definitely not saying they're significant, but saying this is "not a climate change issue" is just plain incorrect.