There's a big difference between the persecution, trials, and worldly tribulation that we must suffer as christians while we are in this world and God's wrath. We were certainly told that we would endure the former, but where does the Lord say that His church was appointed to suffer under His wrath? Nowhere. The time of the tribulation will be a time of the outpouring of the Lord's wrath unlike anything that has ever been seen in history or will ever be seen again, and yet there are those people who argue that the church is appointed to suffer under this wrath. Did the Lord leave Lot to suffer in Sodom when fire rained down from heaven? No. Did the Lord leave Noah to suffer the punishment of the flood in the ancient world? No. Will the Lord leave his church to suffer under such things as the vials of judgement that will be poured out on this world during the tribulation period? Based on the Lord's precedent decisions, it appears that the answer is no.
Why did the Lord mention that the days when He was coming back would be like the days of Noah? The way I read the good news, we should look at what happened in Noah's time and expect the same. Noah was taken into the shelter of the Ark while the world died around him under God's wrath, does the Bible not say we should expect the same thing in our time?