I did a quick googling to get some numbers, and it looks like in 2022, 28% of US emissions were from transportation. Another 25% was from electricity generation. Fix those two things alone and you’ve more than cut your emissions in half.
Getting people to switch to electric cars will go a long way towards slowing down/stopping climate change, and is actually doable. In North America, getting everyone to change their lifestyles, redesigning city layouts, and actually building the public transportation to support it is a process that will take generations to complete. We don’t have that kind of time. Better to get people into electric cars now, while we work towards the long term goal of not needing them.
So that source specifically states that the production emissions are a best estimate, and not thoroughly examined in the scope of that study. In the not-so-theoretical case where the grid is carbon free (there are locations in North America where this is very close to true) that completely changes the math on the production emissions. That study chose not to look at that, and instead choose a flat rate that reflected the current average.
Also, I’m not saying that electric cars are the proper solution; I’m saying they are the fastest solution. They are a stop-gap because the proper solutions are going to take too long to implement.