You don't always have to translate men... de, more often than not you don't translate it. Here you could translate it as: The gods did not guard Homer's eyes: but
they have guarded ....
That's much shorter than saying 'on the one hand... on the other hand'
(a little unsure about how to translate para\ tw=n ce/nwn here. To me, "guarded the messengers from the foreigners" sounds like we guarded the messengers against attacks by foreigners.)
I see what you mean... it's not really clear in English what the meaning is. To make the meaning clearer you could attempted a freer translation maybe: Since we guarded the messengers the foreigners sent... or similar
But normally it's always better to stick with what the Greek says. I wouldn't worry about your translation though, it's good, you know what the meaning of the sentence is, so if you wanted to you could always give a freer translation.