I think a lot of it had to do with setting expectation from Mac's point of view.
The fans - We didn't know what we'd get out of his first year, anything from 5-7 to 15-0 (realisticly 10-11 wins was the ceiling). And here he went and won the East with a 10 win season. He needs to keep the fan base tempered (not easy to do with as unrealitcily demanding we can be), so he can't win an NC the first year knowing we'll expect one every year. He needs room to grow. I think this is is partly true, but no coach ends his season thinking "I need to lose a few games to keep the fans at a sane level".
The players - Consider the only bowl experience on this roster (ignoring red-shirts) would be a loss to Louisville in the 2012 Sugar Bowl, Christmas with the family for the 4-8 bowl season, and most recently a win in the 2015 Nobody Cares Birmingham bowl. There's no experience for what it takes to make it to a quality bowl (much less a playoff spot) and compete once you get there. He can use this meaningless Citrus bowl for building the future = lack of preparation and focus by the leaders makes a piss poor showing on the field and drops their NFL stock. Message sent - either you are here with us day in and day out, focused on winning, or you have already checked out and are of no use to us. Leaders need to set the example and hold the others accountable to that example. Let that sink in for next year's team that wants to achieve something meaningful. I think this had a more significant role in us showing our ass on national television.
Aside from any degree of conscious decision making to not tighten down on everyone and get solid bowl prep work done, I think a huge aspect was he still was dealing with a sht hand. He had a QB he's known since spring practice couldn't get it done, and it had proven out over the back half of the season. He had several players either injured or doing stupid stuff to get suspended prior to the bowl so his roster gets even shorter. And then there are those entertaining NFL dreams. I get that every year there are underclassmen you depend upon that will consider leaving early - they are good enough to be considering it, so they are likely the better players on the squad. But the mental approach with both the suspensions and the NFL evaluators is not where it needs to be, it is still in the 'Me' mentality and not the 'Team/Us' mentality. You can still get NFL evaluations and make a decision, but that can't be the foremost in your mind if you are preparing for a bowl game; the foremost thought is 'what do I have to do to help us win'. IMO, Mac didn't have a team with the right mental makeup of 'team first' to properly prepare for this bowl game; so rather than fight it, he chose to go with it and let it set the lesson for what happens when players come in with the 'me first' mindset. It's the Citrus bowl, nobody cares. I believe THIS was the major factor for any 'lack of preparation' that might be attributed to him - that he decided he couldn't make them care, so he let them experience this type of bowl game in hopes they'd understand why he drives them so damn hard in future seasons. Your leaders of the future will remember this humiliation and hopefully take the lead with the others on doing what is required.
