For me, this boils down to the fact that you're lazy.
He was objecting to me not wanting to write HTML end tags. If you ignore the tone, that might be read as snotty or offensive, then I think there's an important lesson.
Yes, I am a lazy programmer.
I am lazy in the sense that I don't want to spend my time doing hard, tedious work that a computer can do for me. In the HTML example a computer is ideally suited to figuring out which tag I was thinking of closing. And it can tell me when I've missed something. And it will go horribly wrong if I don't get the nesting right.
Here's the thing: getting the nesting right is the thing I need to do. That's what I need to be using my brain for, not for something the computer can do. And if you give me the 'freedom' to mess up the tag closing then you create the mess we have today in HTML: all sorts of documents that require someone else to spend enormous effort to write a parser to cope with my mess. Giving me the luxury of being lazy about not correctly balancing the tags, means someone else has to undertake the Herculean task of being compatible with all the web pages out there.
It's also a bit like garbage collection. Do I want to remember to call free() for every malloc()? Not really, I just want to get memory and use it and discard it when I'm done. And sometimes I want to use C and get into the guts of memory management for speed: that's when I've swapped laziness for hard work because I need to do that hard work.
And there's another sort of lazy that I want to be: lazily evaluated. Don't compute things until you need them, and don't make me figure out when they are going to be needed.
There's great freedom in laziness.