Are all controversial matters subjective or relative?

Yes.

con·tro·ver·sial (kŏn'trə-vûr'shəl, -sē-əl)
adj.
Of, producing, or marked by controversy: a controversial movie; a controversial stand on human rights.
Fond of controversy; disputatious.


Disputatious means the subject can be argued -- which means there is more than one set of beliefs or opinions. That's subjective.
subjective

adjective

Based on individual judgment or discretion: arbitrary, discretionary, judgmental, personal. See opinion, surprise/expect.

Controversial matters are typically subjective because they involve differing opinions or interpretations. This means that people's perspectives on these matters are influenced by their own personal beliefs, values, and experiences. What one person considers controversial, another person may not. Therefore, the controversy surrounding a topic is often relative to an individual or a particular group's perspective. It is important to note that not all controversial matters are purely subjective or relative. Some controversies can arise from factual disagreements, which can be addressed objectively through evidence, research, and logical analysis.