I understand where you are coming from but you can't possibly prevent them from viewing your stuff, as it is on a public blockchain. Even if the site doesn't show it, they can view your stuff if they really want to using other methods.

Steemit will never be for everything. It has to be for those things you are comfortable putting out in public for EVERYONE to see them, including bad people. For some people there may be little or nothing they want to expose to the world in that manner, and that's okay.

The idea of limiting access to being able to comment is a little more complicated but also not something that is particularly well-suited to a blockchain. Again, this platform is for public interaction. That's not for everyone at all times. Use it for what it is good for, and only that.