But it's 2025, and HTML and Word and the APA and MLA and basically everyone agree that times and style guides have changed.
I agree that not capitalizing the first letter in a sentence is a step too far.
For a counter-example, I personally don't care whether they use the proper em-dash, en-dash, or hyphen--I don't even know when or how to insert the right one with my keyboard. I'm sure there are enthusiasts who care very deeply about using the right ones, and feel that my lack of concern for using the right dash is lazy and unrefined. Culture is changing as more and more communication happens on phone touchscreens, and I have to ask myself - am I out of touch? No, it's the children who are wrong. /s
But I strongly disagree that the author should pass everything they write through Grammarly or worse, through ChatGPT.