Well, readers can explore the issue of Belloc’s antisemitism for themselves: the Wikipedia article is a good starting point (though, given the limitations of the Wiki enterprise, not likely more than that). 

Personally, I couldn’t care less. I detest this puritan style of “writing out” from history everyone whose opinions were not precisely congruent with the thinking of college-educated Americans in the late 20th century. Belloc was a fine writer and a gentleman. He was a good poet of the second rank, and a doggerelist (?) of the first rank, if there is such a thing. He wrote essays on an astonishing breadth of subjects, probably a broader breadth than he was really competent to cope with, but almost invariably with some original or interesting insight. To the best of my knowledge, he never did any harm to anyone. He defended his faith (which is not mine) with ingenuity and vigor, and seems never to have subscribed to the near-universal Catholic anti-semitism of his time (“They killed Our Lord” etc. etc.) His opinions were not wildly eccentric in his time and place. His essay on Islam should be taken at its face value, not regarded as tainted because his opinions on other topics would get him chased out of public life today. Belloc does not live today. He lived a hundred years ago.

For goodness’ sake. Many of the things we hold to be self-evident truths will look silly or obnoxious a hundred years from now. No doubt some of those being chased out of public life in our time will be regarded by our grandchildren as heros and martyrs. So it has always been in past times, at any rate. Let’s use some historical imagination. Our own age is not the summit and end point of all human understanding. In many respects it is a stupid and frivolous age. ~John Derbyshire

Hear, hear!