Last week we saw that God cares about human rights - that he wants humans to flourish, whether they have a relationship with him or not. This focus on "human rights" and human flourishing continues in Amos 1:9, which says, "Thus says the LORD: 'For three transgressions of Tyre, and for four, I will not turn away its punishment, because they delivered up the whole captivity to Edom, and did not remember the covenant of brotherhood'" (NKJV). Unlike the capital city of Gaza as the representative of all the Philistines in Amos 1:6, the city of Tyre in Amos 1:9 was not the capital of the Phoenicians.
In many ways, the Phoenicians were a lot like Arabic tribes: they were a loose network of clans that engaged in international commerce, and as such were empire-like without necessarily being an empire. Nevertheless, it is obvious that their mercantile endeavors brought them into some less reputable lines of business - and this is why God has a problem with Tyre (and I imagine other Phoenicians). When God speaks his "thus says the Lord" against Tyre, he echoes some of what he said to Gaza: entire populations were captured by Tyrian raiders and handed over to the Edomites. But what Amos 1:9 describes is an even darker enterprise than what occupied Gaza's attention.
The phrase "delivered up the whole captivity" in Amos 1:9 is a little tricky to translate from Hebrew. It literally means "they delivered/captured/imprisoned all the captives/exiles." Depending on the translation, Tyre's sin could either be that they habitually took entire villages captive as slaves, they negotiated the purchase of entire village populations as slaves by wealthy foreign nations, or their raids were only focused on catching people (rather than inanimate loot) and exiling them from their homes. Whatever the exact sin, God is obviously upset with Tyre because of her barbaric practice of enslaving and deporting people far away from their ancestral lands.
Friends, God gives people homes and places to live for a reason - and he doesn't like it when others violently and viciously deprive us or others of those homes, because "thus says the Lord."