I'm rewatching the series and just got to this one. I like the episode overall, and agree that it usefully extends the "anti alien paranoia" thread that eventually becomes so important to the story. The one drawback for me is Shaal Mayan. I find her patronizing and infuriatingly smug, getting snippy with Garibaldi as he's trying to investigate the attack on her, or lecturing Londo on the power of love (not that he couldn't use one--I just object to her tone, and her as the messenger). The worst is the final scene, where she and Delenn and G'Kar are tut-tutting about how full of hate the humans are "for no real reason." Well, lady, trying to exterminate your race has a tendency to tick you off a little. You'd think as a supposedly sensitive poet, she'd get that.
Still, it's a minor blemish in an otherwise good story in a sometimes blemished but overall amazing sci fi series.