This just isn't true, greens do mean safe in this scenario. If they're not covered by enough players the entire platform takes massive damage resulting in everyone dying. Currently people are circumventing it, by gliding off and getting far enough away from the platform, or eating the death respawning and running back. Both of those options are faster than an average player doing a wisp phase.
If you send no one in greens period, it just stalls the event forcing everyone to wait the 2 minutes and you're left with 0 crystals to use as cover for the wave/wipe mechanic. But as long as one person gets sent it checks off the mechanic, and the amount of time the squad takes ressing and running back is about the same as the experienced player running a wisp. (Which is less than the 2 minute timer on the mechanic).
Previously before today's patch people were sending one person to get whisp'd, then having them use their personal jade waypoint to get back extremely quickly. After the fix to the WP now organized groups including the one I got my turtle in are sending anywhere between 3 and 5 experienced players for whisps, but it's still wiping the entire platform unless you glide.
It's still silly that people are eating an entire mechanic because it's easier to do than trusting everyone to do whisps. There's no incentive to do them when you can send 1-5 experienced people and bark angrily at others to make sure they don't stand in it, then run back after dying. The entire mechanic is just flawed, among other things. Doing whisps properly should earn you more time, or more damage in the form of a debuff on the boss, or both.