I returned everything back as it was before my edits. I was a too quick with my edits, I am sorry - but I was a bit frustrated with the wrong access tags (and therefore wrong navigation instructions from my app) and I lost some 2 hours by circling around the area in order to get to the Otto-Wagner-Kirche. 

I try to summarise the as-is status in order to make an agreement on the tagging which reflects the reality better than now:

These gates are guarded by security staff who does not allow to pass the tourists heading to the Otto-Wagner-Kirche:

https://www.openstreetmap.org/node/10220621952
https://www.openstreetmap.org/node/10220621937
https://www.openstreetmap.org/node/8002030652

These gastes or ways are locked (as far as I remember correctly):

https://www.openstreetmap.org/node/3539388772
https://www.openstreetmap.org/way/676456334
https://www.openstreetmap.org/way/966561573

There is a temporary wired fence at least on these places (see the red line in these pictures). The fence continues further :

https://ibb.co/6X8Yk48
https://ibb.co/TthmnGh

I am not exactly sure what the "Erholungsgebiet Steinhof" area is, but anyway the close vicinity of the Otto-Wagner-Kirche is accessible from the woods from north side.  The museum Gedenkstätte Steinhof (https://www.openstreetmap.org/way/347696594) is,  I would say, not accessible or I can not imagine how would I get to them through the wired fences and security guards.  As for the signs on the gates I can not say much as I do not speak well German. Anyway the security did not allow us to pass to the Otto-Wagner-Kirche and current access tagging is just wrong. 
