Reddit definitely does not have the tech focus hn does. Maybe it did in the long past, but not anymore. Definitely not a substitute for Reddit content without the trolls.
It makes no sense to talk about Reddit and HN as if they had the same scope. It would be more appropriate to compare HN to a particular subreddit.
There was a time when Reddit did not have subreddits (or even the ability to comment). During this time, Reddit's community was very much like HN is currently. It was mostly techy people who found Digg was getting a little too "low brow". It may not have been explicitly tech focused, but it may as well have been.
HN was delibrately set up to be "what reddit was at the start"
To me HN is more like 1999-2004 era slashdot. Certainly not like reddit.
/r/programming is quite excellent much of the time. Reddit generally doesn't have a technical slant, but there are many great subs which do.
Oh, but it does. You won't find it on popular general subs like /r/technology, but there are really dedicated subs for everything, if not more, that you would want to find.
Some subreddits are very technical, and also some content from Reddit ends up here.
With the right subscriptions Reddit is quite more technical while HN is still more entrepreneurish.
There are some great startup/business/legal/finance subs, too.
HN is known for its cynicism
Being cynical isn't the same as trolling though.
I see both cynicism and optimism here in different parts.
Yes the moderation team here does an excellent job balancing both sides of the challenge vs. offend dichotomy.