What if violation of the civil rights of a minority increases the sum total of pleasure pf the majority? ​

The question that you have posed is rather interesting. However, it indicates a misunderstanding of the nature of civil/human rights as they are currently framed.

Step-by-step explanation:

The key thing to recall is that human and civil rights are, for the most part, individual rights, as opposed to group/societal rights. See, for example, the USA Bill of Rights, European Convention on Human Rights, Universal Declaration, and the International Covenant on Civil and Political Rights. Therefore, there is no greater societal sum equation to assess when looking at high rights. Indeed, individuals from minorities are often given special protections within human rights treaties/regimes.

However, it should not be forgotten that many rights are not inalienable, for example the right to family life, or freedom of expression. In these instances the right may be legitimately violated, if, on balance it is required to protect another individuals human right (note that it's individual as opposed to societal), or if it is deemed proportionate to violate that right (eg, to detain an individual because they have breached a provision of criminal law). But, it must be noted that this has nothing to do with minorities or majorities.

The often cited reason for this formulation is that the majority of the human rights treaties mentioned above emerged following the atrocities of the Second World War. In this regard, it must be recalled that one of the underlying philosophical beliefs of he Nazi regime related to the greater good of society, with it being perfectly permissible to violate the rights of one in order to further the welfare of others.