Translation:Muslims go to the mosque five times every day.
This is not true, Muslims pray 5 times a day. Being in a mosque is not required in order to pray.
An English speaker would say "Moslems GO to THE mosque ..." When you here someone say something like Moslems are going ... that's how you know they are Israeli ;)
In Hebrew המוסלמים is definite, why is it not translated with 'the Muslims' in English?
Wow, it is difficult question. I suppose you could say, "The muslims pray five times a day.", but it is more idiomatic to say "Muslims pray five times a day." The difference is familiarity or formality. "The muslims" is much more formal, as if "the muslims" were some obscure people you are just reading about in a museum or journal article.