Is detection of abusive content the same as sentiment analysis?
No. These are two different things.
Indeed, abusive and problematic content often overlaps with negative sentiment. But it’s not always the case.
For example, when someone is advertising “high-quality cocaine”, the sentiment is clearly positive, but it’s criminal activity that needs to be tagged as abuse.
When someone is exchanging contact details, the sentiment is neutral; however, it still can be marked as external_contact. Racial slurs can easily be used in utterances with positive sentiment, too.
On the other hand, “very negative sentiment” does not necessarily mean cyberbullying or hate speech. Even utterances like I hate him are not personal attacks, as they are not aimed at someone participating in the current conversation. Read more about what constitutes a personal attack.