To trample on people means to treat them in a harsh and cruel way (see also Amos 8:4).
The helpless and oppressed suffered under a system that refused to give them the justice the law required (Exodus 23:6–8).
When a father and son slept with the same woman, it showed how morally broken the people of Israel had become. The law given through Moses clearly forbade this behavior (Leviticus 18:7–8, 15; 20:11–12).
profane my holy name: By worshiping fertility gods, Israel and nearby nations practiced “sacred prostitution” (see Hosea 4:10–14). They believed sexual relations with a shrine prostitute would ensure good crops and healthy livestock. This verse suggests these acts were done in the name of the Lord. When performed as religious rituals, these corrupt actions treated God’s name as worthless.