why does import put all clips into the timeline?

I just created a Project and imported all the clips from a folder on my hard drive into it - but the clips were also inserted into my timeline.  I don't remember this happening previously nor does it seem particularly helpful - having 30-odd clips randomly inserted as opposed to being organized in an intentional fashion.

Also, when I try to lasso all these clips to remove them from my timeline, the lasso does not select them.  Why is that not working?

Many thanks.