I see what you're saying, and it does sound logical. But I'm not sure I agree with it, for a few reasons.
1) As you say, look what Tampa Bay did. They embarrassed Chicago, and I think Chicago will come out wanting to prove something. Especially the defense, which wants to be known as the best in the league - the Ravens have taken that #1 ranking in many people's opinion.
2) The Bears are not accustomed to being up by 3 touchdowns. They went into some sort of soft defense (I wouldn't call it prevent, but it definately wasn't their normal scheme) and that's when Tampa Bay lit them up with some big plays.
3) Without their two defensive tackles, the Bears are going to have their fastest defensive lineman in the lineup. Since Detroit doesn't run, they will be teeing off on the QB all day. Even Green Bay, which doesn't have the most prominent pass rush was getting there in a hurry.
4) They want to trade Mike Williams this offseason IMO. He's been getting more and more time in each game. That may take away from the other guy's touches.
5) If you have someone else, why risk it? This is the fantasy playoffs and championship game for some. If you have a better matchup elsewhere, why start anyone vs. the Bears and risk a bad game?