I don't think it's right to say that cells steal revenue - rather, a territory with a terrorist cell does not produce revenue. I don't think the revenue goes to the terrorist player.
Terrorists steal revenue.
From the rulebook:
Terrorist Cells also steal oil revenue from any development present.
If there is no Terrorist Player, stolen money goes into a “pot” for the eventual Terrorist Player to collect.
It's very clear. The money revenue gets collected, even if the Terrorist player doesn't exist yet!