This word "За" gives meaning - the increased excitement of the person who says it. It (the word "За") is used to express discontent with something, dislike of someone. Examples: "Fuck those jerks, and fuck their stupid rules!" This word is a sign of a strong indignation than, for example: "... грубезна книжка", sad thoughts, disgusting and disgusting deeds. Examples: що це за напасть?; що це за похмурі думки?; що це за неохайність? що це за бруд?
And although this word is used to express discontent with something, dislike of someone , it (the word "За") is still not an expression of rudeness.