Unsurprising. The article says what I suspected but was unsure of -- that both the orders of Justice Souter and Justice Thomas were routine decisions that had nothing to do with the merits of the case itself.
The Obama case was dismissed on "standing" grounds, which is essentially the doctrine the courts use to avoid hearing cases they really don't want to hear (see also: The Pledge case). Now, courts do this all the time, but there is something admittedly unseemly about it. If a Justice who is particularly incensed about the practice is faced with a case such as this, what is he do? Should he just let it slide because it'd be really awkward for the court to hear the issue?
The answer might be that the judge should wait for a less politically charged case to present itself with the same issue. The problem is that elections are always politically charged (albeit some less so than this), and in any event, that sort of thinking is precisely the sort that points towards these faux-standing rulings in the first place. So I can imagine a somewhat ornery judge trying to make trouble for his colleagues by sending a message that he thinks they are engaging in extra-legal reasoning -- a point that can be made while still thinking the underlying merits of the case are absolute garbage.