Deleted

I'm pretty sure it has always been that way, at least for a few years. When a game is removed, it is no longer in the Steam API, so support has to manually add the game and they set the last know price to calculate CV. There might be certain situations where the game gives 0 CV, but I don't remember.

This was the process for giveaway list management ever since I joined the site:

1. Automated Syncing -> Turns into $0 value after a game is removed from active listings (and if the store page is completely dismantled, also removes ownership and header data, requiring it to be manually relisted on the giveaway list) [if store page listing changes to new version of the game, it may list the price of the new version instead of $0; staff response to that seems to vary].
2. Manual Configuration -> Set to the last known value before the game was removed. Since this overwrites- and thus compromises- automatic syncing, this is only ever done when staff is certain a title won't be returned to Steam in the future [eg, like how Deadpool kept leaving and returning]. Thus, you mostly see it for games where Valve has banned the developer, though games that've been off of Steam for several years (or where the developer announced an intentional removal) also end up getting manual adjustments.

In short, there's no staff/site bias whatsoever against removed games, it's just that there's a technical/manpower issue related to managing their giveaway listings efficiently. As for your impression, it'd make perfect sense in the context of <games that've been removed but still retain a store page>: Those are ones staff can take years to decide that the games aren't coming back to Steam and, in the meantime, they retain automatic syncing (providing $0 CV all the while). The CV is of course retroactively corrected once the listing is manually edited, if the game doesn't come back (and assuming the community keeps sending in tickets reminding staff to give it proper consideration in that regard).