IMPO, it depends upon the type of criticism. The definition below can be taken in 2 forms:
the expression of disapproval of someone or something based on perceived faults or mistakes:"he received a lot of criticism"
censure, reproval, condemnation, denunciation, disapproval, ... more
- 2.the analysis and judgment of the merits and faults of a literary or artistic work:"alternative methods of criticism supported by well-developed literary theories"synonyms:evaluation, assessment, examination, appreciation, appraisal, ...
If this word falls under the second meaning, i.e., in the case of a supervisor (any race) to an employer (any race), it would not be considered racist. The supervisor is critiquing the work or work ethic of the employee. This critiquing, if the supervisor is a concerned individual, would be helpful to the employee so that he or she can make the necessary improvements in their assignment(s).
If this word falls under the first meaning and the criticism sounds like words "45" and his hateful/hate-filled supporters would express and have expressed, singling out one or a number of demographics of people, then it is racist (definition: a person with a prejudiced/discriminatory belief that his/her race is superior/better than other races).
The rhetoric that is spewed out nowadays is anti-black, anti-Latinx, anti-Jew, anti-Muslim, etc. , and is causing dissension amongst various people, to the degree that innocent people being harassed in the street while minding their own business plus taking care of their normal everyday activities (i.e., going to work, going to school, taking care of family, travelling to buy a meal, etc.).