Why had John Holbrook enlisted in the militia ? How did Judith react?

From the text:

"I think it was his way of breaking with Dr. Bulkeley," explained Rachel. "He has tried so hard, poor boy, to reconcile Gershom’s ideas with his own bringing up. Now it seems the doctor is going to publish a treatise in favor of Governor Andros and the new government, and John just couldn't stomach it any longer. We all think it is to his credit."

Mercy is angry about John's decision. She believes he enlisted because of stubborness.

"I don't!" spoke up Judith. "I think it is nothing but stubbornness."
"That's not fair, Judith," Mercy spoke from the hearth. She looked a little more pale and tired than usual. "I think you should be proud of him."
"Well, I'm not," answered Judith. "What difference does it make what Dr. Bulkeley writes? Now John won't get a church of his own, and he can never get married or build a house!" Her tears broke out afresh.

ok i wont answer becuz u said to answer by october 30th 2017 OH MY GOSH THAT MORE THAN A YEAR