Rev 9 20The rest of mankind that were not killed by these plagues still did not repent of the work of their hands; they did not stop worshiping demons, and idols of gold, silver, bronze, stone and wood--idols that cannot see or hear or walk. 21Nor did they repent of their murders, their magic arts, their sexual immorality or their thefts. "
In the Revelation Satan is at war with Gods kingdom. The saints on the earth are being persecuted ....some christians suffer martyrdom. When the christians join their fellow martyrs in heaven they are struck with Gods beauty that is unhindered. So the contrast of Gods peace and safety and the dangers in Satans kingdom cause them to cry out..How long Oh Lord until you avenge our blood? We must understand that the seals are curses from heaven that are cast to the earth in the fire from the altar..they are fire balls or judgements on destructive rulers..nations that make war.This altar in heaven is where the prayers of saints on earth are collect as they rise to heaven like the ot burnt sacrifices.. so we are pronouncing the curses in the Psalms that rise to heaven in unison with the saints who are demanding justice on earth. This is the character of the opposition on earth.Ps 141 2 May my prayer be set before you like incense;may the lifting up of my hands be like the evening sacrifice.... Yet my prayer is ever against the deeds of evildoers;6 their rulers will be thrown down from the cliffs,
and the wicked will learn that my words were well spoken.
7 They will say, "As one plows and breaks up the earth,
so our bones have been scattered at the mouth of the grave "
Anyone with any sense knows that our war on earth is won in this direct link with heaven.