Some Scottish football figures have questioned why crowds will be limited to the same total at both the biggest and smallest grounds in the country.
Speaking to Sky Sports News on Thursday morning, Scottish Professional Football League chief executive Neil Doncaster said: "We have been in constant dialogue with the Scottish Government. We have been clear that in outdoor stadia, it's difficult to understand the justification in stadia that hold upwards of 60,000 people why just 500 are allowed in."
Swinney faced a similar question from fellow SNP MSP John Mason during a meeting of the Scottish Parliament's Covid-19 Recovery Committee.
"I think the key point here is that we've got to take decisions based on making sure such judgments are effective," Swinney said.
"So let's, for example, take the model Mr Mason has put to me of a variation reflecting stadium size and stadium facility, then I think we lose clarity of messaging, which is a rather blunt one.
"And I make no apology for being so blunt, that we need to quite simply reduce the degree to which people are interacting.
"A total of 500 as a maximum for outdoor events sends a very clear signal to people in the country that we have to reduce that interaction."
Swinney added: "The second point is that we have to make judgements that are effective in actually practically reducing the circulation of the virus, and that's about recognising that there will be limitations on the degree to which venues can accommodate individuals.
"As for the specific numbers, well there is no perfect science here other than the fact that we have got to take clear and understandable decisions."
The SPFL board reacted to the new restrictions by postponing two of three rounds of cinch Premiership fixtures over the festive period, with Boxing Day matches going ahead with limited crowds.
Doncaster admitted that the "overwhelming view" among clubs on Tuesday evening was that all three rounds should be postponed. Only Rangers and Ross County wanted all games to go ahead.
Doncaster added: "We only have two available slots prior to the split and when we met with the board there was a broad view that (Hibernian chairman) Ron Gordon's very helpful compromise suggestion of playing on Boxing Day but postponing the December 29 and new year games was the right approach.
"We know that it causes difficulties with further congestion and we have been clear with the clubs about that, but there was an overwhelming view from the clubs that we should be postponing games and the responsible thing for the board to do was to listen to that view and respond to it.
"Ten of the 12 wanted to postpone fixtures and the two that didn't clearly expressed views that we already have fixture congestion in the schedule and by postponing fixtures voluntarily all we are doing is making that worse.
"From the league's point of view, clearly we want as many games played as early as possible. So we understood that view but ultimately the vast majority of cinch Premiership clubs wanted to postpone fixtures and that's where we have got to.
"I think it's been a bad week for Scottish football in terms of the restrictions but a good week in terms of the democratic process and the league being able to respond to the views of its member clubs."
With concerns that the restrictions could be extended beyond three weeks and no further room in the fixture calendar to postpone matches, clubs are worried about the financial impact.
Doncaster stated the league hoped to get clarification on Government funding within the next week.
"The situation has been crippling and continues to be crippling for the cinch SPFL clubs and it's vitally important that we get as much financial support from the Scottish Government as possible in light of these Scottish Government restrictions," he added.
"I think the Scottish Government do understand how critical finances are in Scottish football and how important it is that we get as much funding as possible as soon as possible."