It's more accurately a proxy for the applicant understanding the context of various processes and the relative importance of a task. That may or may not be a skill you need in the job.
Finally, if the resume error rate is higher or lower than what you observe in the candidate's live, observed writing/coding then you should take note assuming such errors are a proxy for what you're looking for.
Bring a resume with typos and your rebuttal and see what happens. The trouble you go through to defend typos will be far more work than fixing your typos. It's mostly automatic.
Reasoning doesn't excuse you from making mistakes, because excused don't make up for those mistakes. In any professional work environment, your mistakes are someone else's paid job to fix.
OP is talking about attitude and mindset. The "I can reason away typos" mindset is not appealing. The "I will do anything to not make mistakes" mindset is.
I mean, that is still what we are talking about here right? Being attractive to employers.
Even Chrome has a spell checker. Not sure the distinction here between code typos and English typos is a valid one.
The OP is saying not bothering to check is the issue, not the specific errors. And this is, by definition, careless. This is a lack of caring for correctness and a lack of awareness of mistakes. It could even be considered a lack of respect, which would be a lack of professionalism, but the OP did not go there.
If you have dyslexia, then a perfect resume that includes your challenges as a dyslexic would be most impressive.
Employers are looking to be impressed.
Don't be an unimpressive bag of excuses.