Does that mean they are both of Jewish background?
Of course not that there is anything wrong with that.
No. Kerry's Jewish forebear is his father whose father was named Kohn -- changed the name to Kerry when he immigrated. If you look at the chart you can see that he is not in the line descended from the Reades.
The major difference between J effin' Kerry and George W. Bush is that Kerry did not inherit the "class" genes from his forebears. He inherited only the whiney, self-centered, I-am-more-important-than-anyone-around-me, gigalo genes.