Hej! Even if it’s neatly integrated, your Micro.blog timeline and your hosted blog really are two separate things. The timeline shows posts from one or more web feeds (RSS or JSON feeds).
You can, for example, add a YouTube RSS feed from another person’s channel, and their videos will start to show up on your Micro.blog timeline. Removing a one of those video posts from your timeline won’t delete the original YouTube video, though.
The same is true for clicking remove in the timeline for one of your own blog posts; it won’t delete the original blog post.
This also means that if you keep the original blog post around, it will soon reappear in the timeline the next time the web feed is imported. See also my earlier reply here for additional context.
Update: This turned out the be a lie, read on…