Yanbu, I think.
I had a similar quandary about 2 years ago. I had emailed to ask for some curtains that a lady was giving away. I was lucky enough to be offered them, and when I collected them I found that they didn't fit my windows. I could have passed them on to a charity shop but I sold them on as they were very nice, and I felt really bad about it!
But then I realised that I had freecycled several things myself, because I wanted them gone, and I didnt give a stuff what anyone did with them - in fact I'm pretty sure some would have been sold on. Good luck to them if they want to do that with my old stuff, as long as they can be bothered which I couldn't, and it stays out of landfill! If it can earn someone some cash they badly need then I am fine with that.
The ethos of Freecycle IMO is to keep stuff out of landfill and so what the recipient does with the stuff, as long as it isn't premeditated too much, is fine.
I think the lady I got my curtains from wouldn't have cared at all, and it would have been embarrassing to ask her permission and sounded rude when in fact I thought they would fit my windows and they didn't.
If she had been concerned about the further use of her items she could have specified she didn't want them sold on, and I could have then returned them to her or re-free-cycled them.
I don't think there is a clear cut answer to this though really. Some people care about the things they give away and some don't mind. I personally would be glad for you if you could use the money.
What upsets me more is people who have shops, yet buy from charity shops in order to sell on. I saw a little crib I wanted for ds1 when I was pregnant, and missed it - later that day saw a person with a poncy 'retro shabby chic' shop taking it to their premises, it had been £4 and they had a massive price on it by the next week.
That makes me quite angry.
But you didn't do it as a business opportunity, it just was something that came your way. you can pay it forward when you're more flush