BB would never give a straight answer to this; he would pick dry answer number 18, combine it with dry platitude number 10 and end with the usual refrain. It would go something like this:
"We were thinking of drafting him at 21 but were excited when he was still there at 29, blah, blah. We did what we think was best for the team, blah, blah, blah..."
[BTW, I think it would be easy enough to write a Python program to generate BB responses, sort of like the online Dilbert Mission Statement generator (before they pulled it)]
That being said, I have to assume that they did want to trade back again, really badly, but could not find any suitors. But they had blinders on for Strange...the good news is that in years to come, the Strange pick (and the trade down from 21) will provide endless fodder for aholes with 20/20 rear view vision like me to say, "They picked Strange when they could have picked so-and-so..."