The one reason not to use jQuery is that nobody is learning this library anymore so you're creating an outdated code that fewer and fewer people will be able to understand. But if you're the only one that will be ever interacting with the code it's fine.
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
The one reason not to use jQuery is that nobody is learning this library anymore so you're creating an outdated code that fewer and fewer people will be able to understand. But if you're the only one that will be ever interacting with the code it's fine.