Wikipedia:"No valid reason for deletion"

In deletion discussions, people !voting to keep a page will often say that there is "no valid reason for deletion." This is not a helpful thing to say.

The situation
Alice, an unrepentant deletionist, comes across a page which she believes should not exist. For the sake of argument, let's suppose she considers it non-notable. She nominates the page for deletion, cites the general notability guideline, and presents an argument that the article fails it.

Enter Bob. As an experienced Wikipedian and ardent inclusionist, he cites a few sources and then concludes his keep !vote with "There is no valid reason for deletion."

Alice later reads this and gets rather annoyed. "Of course there's a reason for deletion! Does he think I'm some kind of idiot, nominating stuff at random for no good reason?"

Bob may even be right. His sources may thoroughly prove the article's case. But by needlessly antagonizing Alice's nomination, he has discouraged her to respond in kind. The discussion is thus likely to devolve into an adversarial back-and-forth over whether his sources are any good. At the end of the whole process, an admin will have to read through their whole diatribe and figure out who's right, or just slap a no consensus on the discussion and walk away.

Obviously, this kind of argument happens all the time, with or without this phrase. But it's important to remember that the person on the other side of an argument probably thinks their reasons for deletion (or keeping) are perfectly valid. Insinuating that they don't accomplishes nothing and may unnecessarily polarize the discussion.