Of course it's deliberate. That's Microsoft's strategy, along with Apple,
Google or any other company. By associating a common technological term, like
PC (which ironically was popularized with the Apple I if my comp history
serves me right) companies can work with what people already know and become
'commonplace'. This is the same strategy that companies like Johnson &
Johnson, Proctor & Gamble, and Coca-Cola use. Say baby shampoo to someone and
they'll probably think first of this and not this. Say cola or coke to
someone and they'll probably think of Coca-Cola, not Pepsi. This even shows
in image searches.
So Microsoft starts using the term, and Apple along with every other
computer (not PC anymore!) company start using the term because most people
have engrained the formulae 'PC == Windows', 'Mac == Apple Macintosh' and
'Anything == Too techy' into their head, thanks to Microsoft.
Of course, just because it's popular doesn't make it good or right; the
technical term for PC doesn't involve Windows at all. The only 'innovation'
Windows made was that it became popular, not exactly revolutionary. Coca-Cola
was not the first soft drink, but the first cola so that gave it an edge over
future competitors not to mention the ridiculous amount of memorabilia from
Coca-Cola.
Here's an interesting note: Pepsi came out a few years after Coca-Cola,
and Coca-Cola is still more popular. UNIX (basis for Linux and quite popular
then,) came out over a decade before DOS, and almost two before Windows 1.
Which is more popular? Obviously not the former; by the time GNU/Linux came
around, the damage was already done.
So Windows became ubiquitous with PC after Apple's decline during the 90s,
and the rest is history. It reminds me of how the word 'hacker' became so
over-used and dangerous sounding.
This is just the way these companies work. Unfortunately, it seems FOSS
has to work around them until companies see that it doesn't have to be that
way.