I agree, it’s completely unacceptable to introduce a bug and then to instead of taking responsibility for introducing such a bug, you start pointing fingers at everybody else.
It’s like when a car hits a cyclist following all the rules and then tries to blame the cyclist for not following some made up rules that only exist in the drivers head “Cyclists should be on the SIDEWALK if they don’t wanna get hit!”
Not only were they wrong to hit them, they’re DOUBLE wrong for trying to blame them after the fact.