German student in India asked to leave for protesting controversial bill

Governments in almost all liberal democracies (and all other forms of governments for that matter) reserve the right to deport foreigners without cause or due process.

In fact many foreigners have been deported or denied entry without cause (no protesting necessary).

This practice predates W Bush era in the US. Anecdotally it has become more common since W Bush onwards. Hard stats are hard to come by as it is not publicly available data in the US at least.

This is an example of even American citizens being deported in the 1950s under President Eisenhower:

“ The short-lived operation used military-style tactics to remove Mexican immigrants—some of them American citizens—from the United States.“

https://en.wikipedia.org/wiki/Operation_Wetback

A comedy on US citizen being deported in the 1980s:

https://en.wikipedia.org/wiki/Born_in_East_L.A._(film)

participation in political events by foreigners is strictly prohibited by law because that is tantamount to interfering in the political process in india. so it is not incorrect that the student was asked to go.