If you just want to write and not care about tools, there's always LinkedIn. Unlike many tools, people read them.
Having as many readers as possible is not my idea of a blog. Writing is the core idea. Laying out thoughts to yourself and to whoever it concerns.
You can always spread the link to your post via social networks, but you don't have to.
People can find your useful posts years later via search engines amd they don't need a login for the full reading amd commenting experience.