Orban used EU money to take total control of the country (media, poor voters). If EU lets China come into Hungary, it will backfire for the whole EU in my opinion.
China has already targeted Serbia and Montenegro - infrastructure mainly. I can't find the source now, but I have heard they already started investing in Hungary.
I don't know much about Hungary so could you provide a reason why it is bad "if EU lets China come into Hungary"? Unless it is because China Bad, then I'm not interested, but I'm hoping for something more interesting than that. Personally I would hate to see EU close in on itself and so it needs to align with outsiders. China seems just as good a partner as the other big markets to me.
You want someone to explain to you why a certain wine tastes nice but you’ve added a condition that the explanation must not include the most fundamental nature of its taste.