I'm known here for not liking the Sex Pistols, but whether they sang "Belsen was a gas" in poor taste or that idiot Sid wore a swastika muscle shirt - there was nothing fascist about them. It was all adolescent shock value. And remember Jimmy Page's SS cap, Nazi chic intrigues some people. But if Ilan or someone else was offended by it, off it would go.
A tale of two Rics that were actually one (or twins): Roger's Ric was both black and red at different points in time (or he had more than one) and what Pete Agnew plays is (one of) Roger's Ric(s). Very likely at Roger's recommendation as he was Nazareth's producer and guiding light at the time. The Nazareth albums Razamanaz (73), Loud 'N' Proud (73) & Rampant (74) were all Glover productions and on Razamanaz (the album) the Ric sound is especially prominent, just listen here:
That is not Pete Agnew's short scale EB-3 which Glover found lacking in the studio. For years, rumors persisted in Purple fan quarters that Glover actually played bass on Razamanaz (the album), but he has denied this when I once asked him in a q&a on his home site.
Now how Roger's Machine Head, Made in Japan & Who Do We Think We Are-anointed Ric got into the grimy little hands of Sid (I'd have no issues if Glen Matlock had played it) is another matter altogether. I have no idea.