I've seen some of the posts you've mentioned. And you're right. It is a little worrying. However, maybe I'm just being naive, but I'm only a little worried.

First, I would have to wonder about the motivation for these posts. Is it because they are just waiting to jump ship until the other platform becomes available for international audiences, or are they simply writing about other platforms because it is newsworthy and likely to gain attention and upvotes, and therefore likely to get rewards. If it's the latter, I wouldn't mind it so much.

Second, if its the former or some variation of it, then I would just be inclined to stop supporting these people, especially if they are witnesses. (Call me selfish, but I would like steemit witnesses to be loyal to steemit). In fact, I would rather they jump ship sooner rather than later.

I wouldn't be so sad to see these people go because I think there are enough whales and emerging users who can take their place.

Third, while it is definitely tacky to use steemit to lure users away from steemit, there's nothing to stop steemit users from doing the same practices, either. We can just go to these other platforms and advertise steemit.

And finally, I'm hoping that if these posts convince someone to jump ship, its the spammers. In fact, I hope these posts advertising the competition are so amazing that the spammers get so convinced and leave steemit in one fell swoop. Like @darkhorse has said,

Leave steemit to those who believe in it's future.