If you go off half-cock condemning a race/creed/ethnicity on the grounds that there was once a bunch of fanatics of that race/creed/ethnicity and might be more, then yes. You should instead go after the fanatics.
If I start shouting Owain Glyndŵr and waving a red and yellow banner with four lions on it, demanding Welsh independence, and planting bombs on tube trains until I get it then, apart from the fact I should be locked up for madness as Wales would go bust in a day, but aside from the obvious short comings - would that then justify sending tanks into Wales, patrolling the streets with SA-80 clad soldiers, imposing curfews and depriving the nation of clean water and power?
I'd argue that, aside from the clear mental instability of anyone thinking that Wales could support itself economically when all we've got to export is civil servants, the real target would be me and the Cymru Liberation Front...