They believe that Jesus is speaking to them as ethnic jews and not as His Church !
If you're going to characterize an opposing view, you should at least try to get it right.
Jesus was speaking to them as recipients of the Old Covenant, NOT merely as "ethnic Jews." There's a big difference.
The story of Christ and the cross is a tale of two covenants. Once you begin to see these prophecies in this light, it will make much more sense.
3And as he sat upon the mount of Olives, the disciples came unto him privately, saying, Tell us, when shall these things be? and what shall be the sign of thy coming[parousia], and of the end of the world?
That word "world" means age. Here is a better translation of that verse:
{3} As He was sitting on the Mount of Olives, the disciples came to Him privately, saying, "Tell us, when will these things happen, and what
will be the sign of Your coming, and of
the end of the age?"
Matthew 24:3 (NASB)
The
end of the age. What age???
{28} Peter began to say to Him, "Behold, we have left everything and followed You."
{29} Jesus said, "Truly I say to you, there is no one who has left house or brothers or sisters or mother or father or children or farms, for My sake and for the gospel's sake,
{30} but that he will receive a hundred times as much now in the present age, houses and brothers and sisters and mothers and children and farms, along with persecutions;
and in the age to come, eternal life.
Mark 10:28-30 (NASB)
{34} Jesus said to them,
"The sons of this age marry and are given in marriage,
{35} but those who are considered worthy to attain
to that age and the resurrection from the dead, neither marry nor are given in marriage;
Luke 20:34-35 (NASB)
{32} "Whoever speaks a word against the Son of Man, it shall be forgiven him; but whoever speaks against the Holy Spirit, it shall not be forgiven him,
either in this age or in the age to come. Matthew 12:32 (NASB)
{6} Yet we do speak wisdom among those who are mature; a wisdom, however,
not of this age nor of the rulers of this age, who are passing away;
{7} but we speak God's wisdom in a mystery, the hidden
wisdom which God predestined before the ages to our glory;
{8} the wisdom which none of the rulers of this age has understood; for if they had understood it they would not have crucified the Lord of glory;
{9} but just as it is written, "THINGS WHICH EYE HAS NOT SEEN AND EAR HAS NOT HEARD, AND
which HAVE NOT ENTERED THE HEART OF MAN, ALL THAT GOD HAS PREPARED FOR THOSE WHO LOVE HIM."
1 Corinthians 2:6-9 (NASB)
{3} Grace to you and peace from God our Father and the Lord Jesus Christ,
{4} who gave Himself for our sins
so that He might rescue us from this present evil age, according to the will of our God and Father,
Galatians 1:3-4 (NASB)
{21} far above all rule and authority and power and dominion, and every name that is named,
not only in this age but also in the one to come.
Ephesians 1:21 (NASB)
{11} For the grace of God has appeared, bringing salvation to all men,
{12} instructing us to deny ungodliness and worldly desires
and to live sensibly, righteously and godly in the present age,
{13} looking for the blessed hope and the appearing of the glory of our great God and Savior, Christ Jesus,
Titus 2:11-13 (NASB)
The "end of the age" about which the disciples asked in Matthew 24:3 was the end of the age of the Old Covenant and the removal of the kingdom of God from apostate Israel, marked by His return in judgment upon the GENERATION that crucified Him.
His "coming on the clouds" was a reference to the manner in which God - in the Old Testament - came in judgment upon nations for their sin and disobedience:
{30} "And then the sign of the Son of Man will appear in the sky, and then all the tribes of the earth
[literally "LAND"] will mourn, and
they will see the SON OF MAN COMING ON THE CLOUDS OF THE SKY with power and great glory.
Matthew 24:30 (NASB)
{64} Jesus *said to him, "You have said it
yourself; nevertheless I tell you, hereafter you will see THE SON OF MAN SITTING AT THE RIGHT HAND OF POWER, and
COMING ON THE CLOUDS OF HEAVEN."
Matthew 26:64 (NASB)
"Coming on the clouds" was a metaphor taken from the OT:
{1} The oracle concerning Egypt. Behold,
the LORD is riding on a swift cloud and is about to come to Egypt;
The idols of Egypt will tremble at His presence, And the heart of the Egyptians will melt within them.
Isaiah 19:1 (NASB)
Take it for what it's worth.