Complex sentence: NAACP leader Roy Wilkins also opposed the case due to Murray's "not diplomatic" release of her correspondence, and concerns that her sexuality might undercut the case may also have played a role in the decision.
Split into simpler sentences: NAACP leader Roy Wilkins also opposed the case due to Murray's release of her correspondence, which he considered "not diplomatic". Concerns about her sexuality may also have played a role in the decision.