Swift, who is at the Tour de France with UAE Team Emirates, was collateral in the stage four jostle between Sagan (Bora-Hansgrohe) and Mark Cavendish (Dimension Data) and has struggled since, unable to realise the pre-race form he showed on Alpe d'Huez at the Criterium du Dauphine.
"Watching it quite a few of times it was quite a difficult situation. I've gone backwards and forwards with my decision about what I thought should have happened," Swift said.
"I think maybe it was more down to the first crash where he [Sagan] was at fault in that, and then a little bit of him pushing his weight, quite a few people have been pissed off with that, so it was more about setting an example.
"It was quite a hard example to set. I think actually throwing him out - because none of it was intentional, it wasn't done maliciously or anything like that, it was a racing incident - was a tough decision.
"There's been no real lead-outs as such. The first day there was a lead-out whereas now it's every man for himself and they're all fighting for position."
Swift challenged the perception that he is a, albeit versatile, sprinter at the Dauphine when he and breakaway survivor Peter Kennaugh (Team Sky) matched on the Col de Sarenne last month. But the crash that left his back badly bruised, coupled with illness, has inhibited such performances from the 29-year-old through undulating stages that have led to the Alps.
"I've never been a pure sprinter, and I've never been a climber. I've always been good in those middle mountains. And let's not forget I was in the break, so we had an advantage on the climb. It's not like we rode away from the GC favourites on the last climb. It was a bit of a different scenario," he reflected on the Dauphine.
"But I definitely think maybe I left my legs up there somewhere. I've not been the same since then."
Regardless, Swift is focused on arriving in Paris and may have one last shot at line honours before then.
"We've not really seen any breakaways go to the finish yet, and the sprint days with Marcel [Kittel] being so dominant you would have thought more people would be fighting for those breaks. But nobody has been that interested," Swift said.
"It's not over yet. The Tour is the hardest race everyone is in peak condition so as soon as you put yourself in a little deficit with a crash or bit of illness, it's so hard to make a difference. I'll keep trying and pushing."
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