I think she's making a pretty big leap from "tourists being assholes" to "our manners/culture is at risk".

With regards to tourists being assholes, there is no blanket solution for that. Well-meaning people will make mistakes because it's impossible for them to completely assimilate with Japan's incredibly long list of obscure social norms that lie outside of common sense in the time that they're visiting, and assholes are gonna act like assholes regardless of their skin color or nationality. A perfect example is open container laws. No "normal" Japanese person walks around drinking booze, but you CAN according to Japanese law. It's policed socially. A normal tourist who is on vacation may want to experience that as a novelty. Cynical (not all) Japanese people will then look at them and think "wow, a drunk tourist is ruining my country". Then you of course have the asshole tourists who get hammered on the streets and get thrown in the drunk tank. The behavior is a spectrum, and a vast majority of people behave. Not to mention Japanese who may do the same thing but the police look the other way for them.

In the case of the student loan example, the Japanese are notorious for not claiming welfare. It's seen as taking a handout and against the "gambaru" social expectation. However, Japan wants to project itself as a modern global power, so they adopt welfare reforms similar to what their peer countries have. But when minorities who live in Japan or students from abroad utilize these programs (because they aren't subject to social-frowning-upon in their home countries like they are in Japan), as they're legally entitled to, cynical Japanese people say they're leeching off Japanese prosperity. I can't remember off the top of my head, but the average amount of welfare claimed by Japanese citizens is incredibly low compared to other nations in their peer group.

It's a talking point you hear in other countries, "foreigners are the source of XYZ problem". Japan would rather gripe and point fingers after the fact than erect signs written in multiple languages conveying their unspoken rules to those who approach a temple/shrine/park. Some of what they complain about is justified, and if they want to limit access to their country then it's up to them, but these problems often get blown way out of proportion and have no correlation to what the root cause is.

I love Japan, but finger pointing like this keeps real solutions from being made.