I think GP is using "hostile" as a synonym for "malicious". Yes, Clippy was disruptive to your workflow, but it wasn't (as far as I know) exfiltrating private data, installing malware, trying to sell you on Bitcoin, etc.
It may not seem that way now, since even visiting a simple blog page consumes far more processing power than an entire Windows boot sequence from that era and no one thinks twice about it. But when Clippy was introduced, processors were slow, resources were tight and squandering CPU time for no good reason brought it close to being considered outright harmful.
It was, and we rightfully called software doing it "spyware", or more generally "malware". Today we call this "telemetry" and somehow it became standard practice in software engineering.
This is a difference of degree, not of kind.