Yes, an example that confirms the disconnection of reasons and restrictions: there are also speed limits for “Luftreinhaltung” (controlling air pollution), and some people driving eletrical vehicles had been speeding, arguing they wouldn’t pollute more when driving faster — were fined, went to court and lost.
There is also a reasoning from the ministry of transport: doc17384020210526103100_geschwaerzt.pdf in request „Geschwindigkeitsbegrenzung „Luftreinhaltung“ für E-Autos“ - FragDenStaat
basically they say it’s for equity, and for safety (and “it could confuse people”). From this context it also seems that in Austria the situation is inverted, electrical vehicles are exempted from such speed limits.