It’s not that it’s on the 172.16.0.0/12 range. That’s totally normal and used for all kinds of stuff.
It’s that it’s in 172.16.42.0/24 which is the default dhcp settings for a wifi pineapple. It’s the /24 mask given on the .42 that’s a little suspicious because that’s not a common range for anything else.
Being assigned one of those specific 253 hosts with that subnet mask would definitely make me think twice.
It does sound very strange. What kind of anti-China content would ever help a student’s application process? Most of the application documents are about things like English language competency, visa requirements and prior qualifications, not political opinions.