Can features negatively correlated with the target be used?
Negative correlation is not the same as low correlation.
If variables $x$ and $y$ have a correlation value of $c$, then $-x$ and $y$ will have a correlation of $-c$.
When people talk about &quot;low correlation&quot; they usually mean correlation that is close to 0.
In the context of machine learning, negative correlation is just as good as positive correlation; do your filtering based on the absolute value of the correlation.