@Suiseiseki you're having Chinese/English translation issues.
In this context 'viral' does not have a negative connotation, it only describes the way copyleft licenses can spread their terms to derivative works. This is a deliberate design choice made by copyright holders, not a real virus. 'Viral' is a popular term, there is no danger.
The GPL tries to ensure that the freedoms granted by the license are preserved in derivative works. That's a key part of what defines free software. 👋