Students are not being (considered for) expelled for their views of the Tiananmen Massacre one way or another. Taking any stance on that, in this context, would muddy those waters and make Prudue look like it was doing a political purge.
The problem that produced the statement was harassment. Not political views.
I would think that a government machining gunning down peacefully assembled civilians and then running over the bodies with tanks, then shooting any doctors who attempted to help the wounded, wouldn't be politicized. That we can all agree it is deeply and unquestionably evil.
Something being a political view doesn't mean its not verifiable fact.
A debate has different facets - political or not political - fact or not fact - harassment or not harassment.
In this case the problem that needed to be addressed by Purdue was the harassment.
Students debating different understandings of Tiananmen Square (regardless of either sides merits) was not the issue that required intervention by university leadership.
Students are not being (considered for) expelled for their views of the Tiananmen Massacre one way or another. Taking any stance on that, in this context, would muddy those waters and make Prudue look like it was doing a political purge.
The problem that produced the statement was harassment. Not political views.