Yep, all valid points. The plan is to re-add the new project button to the homepage. See Add ability to create new project from Glitch homescreen for details.
The resume coding button loads the editor with the last project you were editing or viewing. We don’t add you to projects at random. To remove yourself from a project, click on your avatar in the list of project members at the top left of the editor when viewing the project. You’ll see the option from there.