It is a constant refrain in “social justice” and “diversity” ideology that under-representation indicates a discriminatory bias:

Under-representation => bias

For example, suppose that 10% of the background population belong to some group A and suppose there is a selection process for a merit position (e.g., job applicants), where the applicants apply at the same rate (10%). Suppose also that only 1% of those selected for that position belong to A. Under these suppositions, it is usually then claimed that the under-representation (i.e., 1% is less than 10%) is caused by discrimination in the selection process against members of group A.

In general, no further objective evidence is cited for such claims (although clearly such evidence might be checked: for example, applicants might describe their interview experience, prior to announcement of outcome; the qualifications of applicants might be compared; records of the selection discussions might be kept). So the principle above is not a conclusion justified by data, but simply an untested assumption.

Are those who claim to be concerned with discriminatory bias against groups generally concerned with under-representation?

Here are the HESA 2014 statistics for the academic year 2012/13, for students in higher education in the UK. In each category, men are under-represented. Overall, men comprise about 43% of UK students, while women comprise about 57%. This varies somewhat from college to college.

This general pattern of male under-representation in higher education has been the case for at least two decades.