Why do people always try to downplay the extremism of a terrorists as a lone wolf if they belong to the same group as the terrorist?

[Anonymous]

Right now in the US there is a rise of white supremacy and religious fanaticism that hasn't been seen since the rise of ayatollah khomeni in Iran before the Islamic Revolution. Also, I don't care if republican or evengelicals get offended or deny it, and if you deny it or deflect towards democrats or communism, you prove the point of my question that those who belong to the same group of terrorists always deny the majority are the same as extremist so they are not help accountable for the same beliefs. For example, whenever you have white person especially a white male there is always white males who rush to their defense especially when guns are involved, because God forbid the terrorists caused them to lose using the guns they love. This usually happens online 24 hours after an attack committed by a white vigilante terrorist and it seems like there is already a troll storm of denialists ready to deny white supremacists are responsible for attacks that support white terrorists. There is correlation between the rise of Extremism in Iran compared to the rise of extremism in the USA.

Islamic Revolution of 1979: The Downfall of American-Iranian Relations (siu. edu)

"hich is the primary center for Shi’a scholarship in the world.17
He opposed the Shah’s regime for two major reasons: American
influence and the secularization of Iranian society. Khomeini believed Israel was a center for western imperialism—primarily maintained by the U. S., and that Israel persecuted Muslims. "

More Than Half of American Jews Believe GOP Bears Responsibility for Record Levels of Antisemitism in U. S: Report (newsweek. com)

The Rise of Far-Right Extremism in the United States (csis. org)

Ayatollah Ruholla Khomeini’s rise to power in Iran (archives. gov. il)

Dozens of Top Republicans Refused to Condemn Antisemitism Rising in the GOP When Asked (businessinsider. com)

Conservatives are more likely than liberals to hold anti-Semitic views, survey finds - Jewish Telegraphic Agency (jta. org)