Breakthrough cases aren't the cause of the US Covid-19 surge

[Ms. Toad]

2. They are not the cause -

they are a consequence, and if vaccinated don't take steps to prevent contracting and spreading, they are a contributory factor.

ALL people infected with COVID can spread it - vaccination status is irrelevant.
ALL people infected with COVID can be the source of variants (and there is at least a strong theoretical basis for that potential being greater in vaccinated individuals)

The issue isn't who caused it - the issue is how do we get out of it wtih the least damage. That includes ALL of us doing our part to avoid contributing to making it worse by masking and social distancing - because even if we did not cause it we live in a community where disease is rampant and becoming a breakthrough case contribute to the problem.