Online discussions of phenomena veer toward ETI because they're a topic that's exciting on the surface.If exocomet fragments are the most consistent explanation then this thread wouldn't exist and SETI would not have pointed it's radio arrays at the star.
SETI researchers pointed arrays at the star because the phenomenon seems likely enough to involve ETI that SETI researchers felt it was worth their time. Which isn't really the same thing as ETI being the most likely explanation.