Why did the developing relationship between the wampanoag and pilgrims make some pilgrims uneasy?

I think the relationship of the Wampanoags and the Pilgrims are uneasy because of the following reasons;
1. The Pilgrims believe that they were outnumbered.  If the Indians would attack, they would be in grave danger.
2. The Native Americans were afraid of the plague that was carried during the travels of the pilgrims. Many of them had seen how people died from this disease and that they didn't want it to happen to them.

Despite, those reasons both sides continued to work together and create a partnership out of pure necessity.