Be a bit strong
Definition 1 of 2
Pro Tip 1/3Express Disapproval
Used to criticize something that seems excessive or unnecessary. 
Telling her she failed completely was a bit strong, don't you think?
Pro Tip 2/3Emotional Impact
The phrase can convey emotional response to harsh or severe words or actions. 
His words were a bit strong, leaving everyone in the room upset.
Pro Tip 3/3Subjectivity
What is 'a bit strong' to one person may be appropriate to another. 
I didn't expect my critique to be a bit strong; I thought I was being fair.