> but why does BuddyPress think it’s not the case that a user should redirect to their info?
That’s just the way it works. By default, the BuddyPress front page is not the user’s profile page.
> Is there a way to code this, without getting into BuddyPress and later regretting it. I don’t want to use anymore plugins.
You can either edit/create bp-custom.php in the plugins directory or use a plugin that someone has created like bp-profile-as-homepage. If you look at the code for this plugin (one short php file), it is very simple. It taps into a wordpress hook to add a check to see if the user is logged in and if so whether the current page is the front page. If it is, then it redirects to the user’s profile page. That seems to be what you want.