Pointing out typos and grammatical errors is basically a derailment tactic. If you didn’t understand the text, then ask for clarification, but disqualifying an argument that you clearly understood because it has a typo or grammatical error in it really is kind of assholish.

Study: People Who Point Out Typos Are Jerks • 2016 Mar 30 • Sophie Kleeman • Gizmodo

If You’re House Is Still Available, Send Me an Email: Personality Influences Reactions to Written Errors in Email Messages • 2016 Mar 9 • Julie E. Boland • PLOS One