Because it's intrusive. There are lots of opinions on how far a website should go to ensure their users select strong passwords, but I implement a strawman pass

Because it's intrusive. There are lots of opinions on how far a website should go to ensure their users select strong passwords, but I implement a strawman password roster. If some of the throwaway sites and forums that I sign up to once started forcing me to select a more secure password it would be extremely annoying and I wouldn't sign up. I'm perfectly happy with my 6 letter a-z password for one time forums, that I use anonymously, and that I might occassionally log back into twice. Incidentally, the password I use is "openit". This password means nothing to me. If you did some detective work on me I'm 100% sure that you would be able to get access to some sites that I use by entering that password. Not having to use symbols, capitals, and strong passwords for these throwaway sites, means that I can effectively maintain about 10 different password sets, where my most important "tier 1" passwords are reserved for my SSH keys and email.