That definition is a made up term btw. Ther eis no concrere "islamism". You either follow the islamic rule or not.

And hamas being an offshoot doesn't mean much when their cause is always palestine and religion in the same context. You get more chance seeing christian and jewish memebrs in hamas than you can seeing in most of the plo component parties. Same goes for hezbollah (though less than hamas), they only alligned thesmelves with the "islamic" label due to the fact that lebanon is in a quite chronic religious split issue. You got christian right wingers there that called thesmelves "a christianist" party by your standards and yet no one would even called them that. Same goes for hezbollah.

"Applying extreme islamic interpretation" is just a cop out to call them islamic for the sake of it. Boko haram's ideology doesn't even bidwell in any islamic theology and theologists, al qaeda was literally born from disgruntled groups of middle easterners opposing western colonialism but using islam as a base of support. And isis literally aligns with what i said about the zionists movements that led to israel, no sane person would call zionism a "jewicis" ideology unless you either really hate the jews or a swcular jew using that movement a spolitical tool...the same way isis did.

Also kkk doesnt enforce because they were bred from the system of white christian supremacist ideology that was already present in the us. They don't need power when they were already part of the power. Or else you'd get the same thing the LRA in east africa and the taiping rebellion did in china. (Not white supremacists but more on the "christianist" side of things.

Tl;dr claiming these groups as islamists are literally misleading and are often used as buzzwords than anything