I don't think so. Most people are stubbornly dogmatic about their beliefs, so having strong opinions is just human nature. Personality has many more dimensions than one singular belief can convey. I doubt I could even assume that much about a person just based on that

When that one idea becomes the majority of your interaction with others ...*sigh* yes.
But, in general, No.

No.

Depends on what topic. Let's say it's a topic I feel strongly about, such as same-sex relationships. I probably wouldn't want to be associated with anyone who thought that same-sex relationships were "wrong".

everyone as their own opinions so i would never actually judge them!

No I accept that opinions differ.