Robert L Thomas’s two volume commentary on the book of Revelation has been the standard pretribulation commentary on Revelation for three decades. On page 472 of his first volume, he makes an admission:
Apparent weaknesses in [my own understanding] of the seal include its inability to explain why the sealing did not come before the judgments of the first six seals, protecting God’s servants from the harm inflicted under the fourth and sixth seals. . . . Perhaps sealing was unnecessary to protect God’s people during the first six seal judgments because of their lesser intensity, but with the more direct nature of His visitations under the trumpets, a decisive step of protection is in order.
Thomas is perplexed why the 144,00 are sealed at this point between the sixth and seventh seal. His pretribulation interpretive framework prevents him from seeing why this makes sense: the first six seals should not be construed as God’s wrath! That is why the 144,000 are not protected before the first seal is opened. The 144,000, along with the innumerable multitude that appear in heaven out from the great tribulation, are protected between the sixth and seventh seal because the day of the Lord’s wrath begins when the scroll is opened at the breaking of the seventh and final seal.
In addition, Thomas observes (but does not understand why) that the first six seals are “lesser intensity” than the “direct” visitations of divine wrath in the trumpets. That is because the great tribulation is not God’s wrath. The first six seals picture the sinful depravity of humanity that accumulate guilt before God, while the trumpets and bowls are God’s consequent judgment against that guilt.
It is incoherent to interpret the first six seals as God’s wrath, when they are clearly signaling the anticipation of God’s impending wrath in the trumpet and bowl judgments.