What if the lead author disagrees with the coauthors on manuscript content and target journals?
It seems to me that choosing where to submit is within the responsabilities of the first author. Even though the acceptance of the co-authors is encouraged and desired in order to maintain a healthy relation, I think the last word is his. 

I also think that there's a lack of empathy in this matter. Co-authors should be asking themselves how would they feel in the author's position. How would they feel if they had an idea, developed methods, analysis and drafts and kept being undermined by the rest of the team?

For closure, keep in mind that a work is best if published, regardless of place. Spending all the effort taken because of such disagreement seems petty and dull to me. It is better to let it go and focus on the next project.