No, it probably doesn't. I suspect the real reason for not supporting Litecoin goes something like:
"I like Bitcoin. Litecoin is a competitor of Bitcoin. So I don't like Litecoin. So I'm not going to support it."
I seriously doubt that is the real reason as SD has been operated very professionally and honorably since its inception.
And it appears from the MPEx contract that it already planned to include other crypto-currencies.
"Profit and Loss Statements" means a statement that lists as a lump sum all Bitcoin income during one calendar month (including non-BTC revenue converted at then prevailing BTC rates) as well as a reasonably detailed break-down, then as a lump sum all expenditure during that same calendar month (including non-BTC expenditure converted at then prevailing BTC rates) as well as a reasonably detailed break-down, thus showing the net result of each calendar month.
So dooglus, drilling down on the implications if that is the real reason then there could be a conflict of interest with the SD shareholders resulting in the bias against LTC.
For example, if one holds a significant amount of BTC and 'doesn't like litecoin' because if LTC were significantly adopted then it could leech from or perhaps even exceed BTC's market cap. This would result in value stored in BTC being significantly eroded if not converted into LTC or some other asset. This may be one of the economic reasons LukeJR is so opposed to LTC. But based on the past performance of SD's management this does not appear, so far, to be legitimate concern.
The bottom line though is that whether LTC is significantly different as a crypto-currency from BTC is completely irrelevant to whether SD integrating LTC can generate value for SD shareholders. And SD management has a fiduciary duty to generate shareholder value regardless of their personal opinions.