Of course the point obvious point here is that the thing that would make Christians more appealing in this scenario is their actual actions, not their beliefs. Those actions would be viewed as "good" for the simple reason that they are the naturally evolved human behavior possessed by most of us. If a majority of Christians started behaving like me, it wouldn't make me want to be a Christian, it would make me wonder why they had been so fucked up for so long.
The answer to that question would be, of course, belief in Christian superstitions, and the exhortations in those superstitions to force themselves on others.
Not to mention the brainless asshole (mercifully removed from the gene pool) who was prepared to put the lives of the Sentinelese population at risk by illegally exposing them to a population of microorganisms to which they have no resistance. The ignorance and arrogance of his actions (how did he plan to communicate with them?) makes him a poster-child for evangelical thinking.