Non-programmers and the lay public do not assume what source available means, nor what open source means, in terms of what you can and can’t do with it. Most lay people would assume that if source is available, then you can do what you want with it. This is what a lot of programmers assumed before OSI and FSF existed. Saying that many people think these two terms (open source, and source available) mean the same thing does not imply that anyone is suggesting that you can’t use code professionally or commercially. It’s a negative assumption on your part to accuse people of weaseling just because they don’t know your industry term of art definition.