Making a comparison between offline photo app with no trackers and without list of permissions and with online Facebook privacy nightmare app seems strange. Facebook is notorious for bad privacy records, do you have at least one similar finding related to Snapseed? Or is it just that Google bought it?
As for those zero trackers in Facebook app, with 75 very strange permissions requirement, Facebook doesn't need any more trackers when you are providing it your with all access.
We can only speculate why Google bought this app. If they saw it as a way to compete with Instagram at the time, or if they could it's capacity use with their social network (Google+), they simply bought a great app, as for instance Apple bought Siri.