my guess as to why tixati isn't open source is it probably utilises a proprietary C++ library written by the tixati developer which is used in his or her own software projects, perhaps as a full time job or consulting for other companies
It's destructive to the whole system, including yourself, to hide such intellectual information. You "made" the program, but really you discovered a set of natural laws which work to produce it. ... Selfishness is okay, but the destruction of you and the environment you depend on out of greed is mathematically inefficient. I'd go so far as to say it's immoral because it's fighting natural tendency towards the most effective machine.
If the developer has nothing to hide then they should make Tixati FOSS as well. There is absolutely no excuse.
> but I've never seen a comment from the developer for why he choose closed source.