well these guys say that doom should have sub-genres for every different technique and subtle difference a band has...ok...by "swallow the sun isn't doom" they're probably saying that they aren't pure doom. Which they aren't...but you can still call em' doom since AT LEAST 90% of the material is doom. If you can call My Dying Bride's records and Katatonia - brave murder day "doom" records, you surely could admit that swallow the sun is doom. Yeah there are some colorful parts, but it's essentially dark, slow and full of despair.