"Astroturfing" is a political concept. It's about making a top-down initiative appear to be a bottom-up one instead. Fake "grassroots". AstroTurf, see?

What you're talking about, as best as I can tell, is called "fanboyism" -- individual devotion characterized by unusually strong vocality and blindness to contradictory evidence.

Fanboys are extremely common in tech, but usually associated with companies that make products with particularly elegant design (Apple, Tesla) or with a strong sociopolitical component to their identity.