This does not speak well of Catholic doctrine. The Muslims don't adore the merciful God, they adore the vengeful god.
This is somewhat out of context, BTW. In context in the Vatican II document, the Muslims are "in the first place" after having discussed (a) other Christians; and (b) the Jews.
IOW, Muslims are "in the first place" after adherents of the religions we recognize as being divinely instituted.
The Muslims don't adore the merciful God, they adore the vengeful god.
That's not what they say, though. In fact, doesn't the Koran begin "In the name of Allah, the benificent, the merciful ..."?