Yes, you are correct. However if an app had ads and was also Free (libre), it could be recompiled and redistributed without ads too. What I meant to convey was that these apps are all GPL, MIT, BSD, etc licensed, and also wanted to convey that they respect you (by not spying on you, or burning your battery/bandwidth serving ads, etc), and are otherwise most likely RMS approved :-). I should have been more clear that they are both types of free.
I should point out that you're conflating free (as in freedom) with free-as-in-beer (ie, gratis).
Free (as in freedom) software absolutely may have ads, or charge for the software.
F-Droid may be 'all of the above' (free as in freedom, no ads, no charge), but that's not necessarily implied by "Free (as in OSI/RMS free).