Firstly there’s no “spam” marker in user profile information.
There are two fields - blocked and muted - which are visible in a user profile, but you can only see a true or false value in the JSON response if you are the authenticating user, i.e. I can see if I’ve blocked or muted a user, but that user cannot see that I have done so. As @episod said previously, this is a privacy issue. If you are not the authenticating user, those fields will show null.
You’ll only get the information you’re referring to ‘x has blocked you’ when you try to carry out an action explicitly prevented by the block (i.e. a follow). You cannot ask the API to tell you whether a user has blocked you.
This would not be in the spirit of applications built on the API.