One thing about the sheep incident btw: The police is investigating two things in that regard - one being the shepherd who claims that the herd basically ran away and sought shelter in the tunnel. The grazing area of that herd is fenced off on three sides, and has a small creek on the fourth side. Police is investigating whether a dog or similar was interfering with the animals, chasing them out of their patch and into the tunnel.
The other investigation is into that apparently a ICE going in the other direction hit a (single) sheep in the tunnel a few minutes earlier. Driver checked for damage and reported the incident. However, the "message" never made it to the train that derailed five minutes later.
As for the second incident with the RB train... uh, not reindeer. It smashed into a herd of cattle ("Rinder") that had broken out of their fenced-off area, were walking down the tracks as sort of a convenient path, and were hit by the train coming around a curve at only 80 km/h. Out of 27 animals, 13 were killed by the train, 5 injured animals later put out of their misery by police, the other 9 survived unharmed.
There haven't been any outcries really - a few calls for highspeed lines to be fenced off, but that's it.
You can't realistically fence off tens of thousands of km of rail lines all over Germany. For wild animals, "green bridges" are being increasingly built (as part of common animal wandering trails, which also include forrested corridors between habitats), in particular across highspeed lines and highways.