"All spoke well of him and were amazed at the gracious words that came from his lips. 'Isn't this Jospeh's son?' they asked." (Luke 4:22)
First we have the Good News of the Isaiah passage fulfilled in their hearing. And they liked that, at first. But then it seems they are not going to believe a word they are hearing. And why is that? And then Jesus tell them this harsh sounding thing and they are furious:
"I tell you the truth, no prophet is accepted in his home town. I assure you that there were many widows in Israel in Elijah's time, when the sky was shut for three and a half years and there was a severe famine throughout the land. Yet Elijah was not sent to any of them, but to a widow in Zarphath in the region of Sidon. And there were many in Israel with leprosy in the time of Elisha the prophet, yet not one of them was cleansed--only Naaman the Syrian."
They were going to throw Jesus right off the cliff, but they did not dare. Can you imagine?
This is another passage, where we don't get any answer to our "why" questions. It was NOT that the people in Nazareth were not told. They were both told the Good News and they were also warned about not, not accepting it because they were too familiar with him. Neither worked even though hey were told so much. They rejected him. You can't fault Jesus. He tried both ways.
And then also, why only the one widow and only Namaan?
I notice these kinds of passages more these days. The only answer is: don't stumble on him. Build on him. Repent and believe and let the rest of it go.