Would the rejection of an argument because of a grammatical error be a type of logical fallacy?
This seems as least similar to the continuum fallacy
The fallacy causes one to erroneously reject a vague claim simply because it is not as precise as one would like it to be. Vagueness alone does not necessarily imply invalidity.
It also could be characterized as a fallacy of misdirection or a red herring
Attempting to redirect the argument to another issue that to which the person doing the redirecting can better respond. While it is similar to the avoiding the issue fallacy, the red herring is a deliberate diversion of attention with the intention of trying to abandon the original argument.