You, in whose hands Fortune has placed the reins of these beautiful regions for which it seems no pity moves your heart, what are the swords of strangers doing here? In order that the verdant plain be painted red with that barbaric blood?
Stanza 2 pulls no punches: it's going to call out the punks who are causing all the trouble.
And who are they? Those "in whose hands Fortune has placed the reins," a.k.a. the ruling class
(Note that Fortune here is the personifiedLady Fortuna, the goddess of plenty and, well, fortune. Petrarch's audience would know that, while she's got the goods, she's also fickle. Fortunes change.)
Petrarch shames the nobility here by reminding them that they've been given control over such a beautiful country merely by an accident of birth (i.e., fortune) and not through merit.
He also calls them heartless, since they are not humbled by their good luck nor moved to civic responsibility by the beauty of the place.
The big problem is also outlined here: those who should protect Italy from the hostility of foreigners ("swords of strangers"—a nice synecdoche here) have invited them in. And now they're bleeding all over the nice green grass.
Petrarch's bold statement of the case is meant as a knuckle-rapping to the nobility and also as a wake-up call.
Flattered by futile error, little you see, thinking you see so much, for you seek love and trust in venal hearts— he with more followers is more surrounded by his enemies.
If you have an Italian grandmother, you understand this syntax. She might say something like "You think you know everything, but you know nothing. The nothing you know is a lot."
Petrarch continues to dig at the Italian nobility by saying that their decision-making logic is flawed.
Specifically, they think they can buy the loyalty of mercenary soldiers—which they can't—and can control them to their own ends—also not true.
In the end, says Petrarch, the nobles who hire mercenaries face a paradox: the more power they buy, the more vulnerable they are to treachery from foreign forces. Oy.
O deluge that was gathered from what strange wilderness to inundate all our sweet countryside! If by our very hands this has been done, then who will rescue us?
Here we get another apostrophe, this time to the hordes of Germanic mercenaries imported by the Italian nobility.
But behind that apostrophe is a reference to the great deluge in the Book of Genesis, which supposedly wiped out mankind because they behaved idiotically. It's no mistake that Petrarch brings this up here.
Notice that Petrarch has no good opinion of people from beyond Italy's borders: the Germans are a "deluge" that will "inundate" or drown the perfect Italian landscape. Xenophobic much, P.?
Petrarch laments that the Italian nobility doesn't know how to keep the best interests of the country at heart. Now who's supposed to help them?