Criticism is not compulsorily negative.
Criticism often becomes a part of our talks, both in our formal and informal meetings. Normal criticism aims to highlight deficiencies, to mend the things, and not necessarily malign the images of a group of individuals or anyone individually. 
Where there are no adverse comments, deficiencies persist unabated. So the content, or more accurately, the words, in a criticism seem to be a tool to do the correction. To keep the criticism desirable and sure to hit, it is necessary to use the most appropriate words. 
The system free of spaces for criticism is largely comparable to a vehicle without brakes. Criticism with bad intentions is definitely undesirable and does damage, whether in a family, at work, or in any teamwork situation. 
A senior tells his junior, "You are not imparting your hundred percent." It reflects negativity, but simultaneously, it is also a fact that has been framed after long observation. 
It requires high-grade skill to express facts in a way that hurts the least the individuals against whom fingers are raised. 
Negativity comes into play only when the intention is nefarious and the occasions are not appropriate to convey harsh words. 
Any language is rich in vocabulary. It is upon us to choose the right words to express our feelings and observations as truly as possible.
Wisdom demands that we get our purpose of betterment achieved by giving no space for negativity to spread.