No ethnic-religious group (or individual family) today want to be connected to slave trade. The first reaction when looking at slave trade in level that brings up examples like this is the accusation of it being a slur.

In reality, if we just look at the Atlantic slave trade, all then existing ethnic-religious groups of any standing in the Atlantic world and the areas brought to contact with it ended up tied with it to some degree, starting from those Africans who did much of the capture of slaves in the interior. 

Through its role in the industrialization of the British Isles the Atlantic slave trade created the modern world. We are all, in a way, beneficiaries of the suffering of those who were the merchandise in that trade.

Yes, there were Jewish merchants involved. Slave trade was "just" another trade - and very profitable one. No, Jewish merchants did not run it.

The Atlantic slave trade grew out of the Mediterranean slave trades branch serving the Occident. The other branch serving the Orient would in time end up creating an Indian Ocean equivalent, of whose most famous example is the Sansibar slave trade, through which up to 50 00 captive people went in the 1860s and as many as 25 000 still as late as 1892. In countries like Saudi-Arabia in the Middle East there are still alive people who were once slaves.

If you want to find a slave trade run by Jewish merchants, one has to go back to slave trade bringing mainly Slavs through Western Europe to the Mediterranean world during the early centuries of the medieval era after Islamic conquest ended East Roman control of maritime trade routes.

Slaves have probably been part of the trade in the Mediterranean world as long as large-scale trade has existed; there is no old port of any significance in the Mediterranean that would not at some point played role in the traffic of captive human beings. 

A group like Jews coming into existence in this this setting were set to end up as both the merchandise and the merchants. One of the earliest examples of Jews in Europe is a gravestone in Athens from around 262 BCE - thought to belong to a Jewish slave. This was centuries before mass enslavement after the failed Jewish rebellions in the 1st and 2nd centuries CE.

As Jews, a formerly oppressed minority, have gotten such a strong position in 'Western' society, they have done what all groups have tended to do in similar circumstances: Use their new position to try to enforce a view of the past preferable to them.

The 'Western' preference to sanctify Jews after the Holocaust has only exacerbated this. The idea that Jews were just like everybody else, in good and ill - neither eternal saints who always suffer nor "killers of god" scheming against Christendom - is something that seems as hard for philosemites to accept as to antisemites.