Because it cost them something. It cost them their livelihood, and it caused a financial burden in their life. Isn’t this so often the case, isn’t it true that where your treasure is there your heart will be also? (Matthew 6:21) And these were pigs non-the-less, a filthy, dirty animal. A representation of everything that was wrong with the Gentiles. They were unclean by definition. But were they incapable, or out of the reach of the Lord? Of course not but they were unwilling. They loved their mire more than they valued the One that could save them from their sin. How often do you turn back to the vomit (Proverbs 26:11) when far greater things await you?