The Jahmiyyah and all their offshoots (Mu'tazilah, the Later Ash'aris, Maturidiyyah) need to deny Allaah is above the Throne, because it invalidates their intellectual proof for demonstrating that the universe is created. They do this through what is called "hudooth ul-ajsaam" - which is arguing that the qualities (sifaat), incidental attributes (a'raad) and occurrences (hawaadith) found in bodies (ajsaam) are proof that they are created, and must have a creator. So when they saw in the Book and the Sunnah, Allaah described with what would amount to them to be a'raad (incidental attributes) such as love, anger, pleasure, and being above the heaven and so on, they had to deny these attributes so as not to invalidate their rational proof. And thus they unleashed themselves against the revealed texts with ta'weel and tafweed in order to protect and save that (corrupt, flawed) intellectual proof from being falsified. The Kullaabiyyah and the Early Ash'aris held that Allaah is above the Throne with His Essence, but negated Jismiyyah (being a body) from Him - so they were different to the others in this view in that they held it was possible for Allaah to be above the Throne, without that invalidating their intellectual proof - so they added phrases like "without contact" and "without confinement" and so on.

The Salaf recognized the falsehood of the deniers and what they were leading towards. So from the things they had to reject was that the Qur'aan is the Speech of Allaah, and that Allaah will be seen in the Hereafter, because Allaah speaking means He is subject to occurrences (hawaadith) and Allah being seen means he would be in a direction, and both of these would mean that Allaah is a body, and thus created - so they had to say the Qur'aan is created and Allaah will not be seen in the Hereafter. And the greatest obstacle to their rational proof was Allaah being "above" the heaven - and so they had to deny this, but they could not do this openly, so they only hinted at it through the other issues, and the Salaf realized this from them through deduction.

Abul-Qasim Sulayman bin Ahmad at-Tabarani brings in "Kitaab us-Sunnah", as does adh-Dhahabi in "Mukhtasar al-Uluww" (p.132-133) from al-Abbaas bin Fudayl al-Asfaatee from Sulayman bin Harb who said:

I heard Hammaad bin Zayd (b. 98H, d. 179H) (saying): I heard Ayyub as-Sakhtiyaani (d. 131H), the Mu'tazilah were mentioned, so he said: "The central axis of the Mu'tazilah is that they want to say there is nothing above the heaven".

And adh-Dhahabi, in his "Mukhtasar al-Uluww" commented on this saying:

This isnaad is like the sun in its clarity and like a pillar in its affirmation from the head and scholar of the people of Basrah (i.e. Hammaad bin Zayd).

And the Mu'tazilah were upon the deen of the Jahmiyyah in negating there is a Lord above the heaven, and we have documented elsewhere that the Mu'tazilah were also heavily involved in debating with the Indian Materialist Philosophers during the time of Haroon ar-Rasheed - see here. And they took up the form of argument of Jahm bin Safwaan against the Indian Materialist Philosophers (of Hudooth ul-ajsaam) but they refined it further, by adopting the "Atomism" of some of the Greek Philosophers, so they adopted the notions of "al-Jawhar al-Fard" (the individual particle" and "al-juz alladhee laa yatajazza'" (the indivisible particle) into their creed in order to refine and strengthen that same proof - and then the Ash'ariyyah simply adopted that from Mu'tazilah thereafter. And all of this was the "ilm ul-kalaam" that the Salaf condemned and rebuked.

But this saying of Ayyub as-Sakhtiyani was said before or around 131H which is when Ayyub as-Sakhtiyani died, and this is because the Mu'tazilah adopted the deen of the Jahmiyyah of ta'teel of Allaah's uluww and Allaah's sifaat, on account of that intellectual proof of hudooth ul-ajsaam.

And reflect upon what Ayyub as-Sakhtiyaani, that great and pious scholar, said about the Mu'tazilah in his time, and Hammaad bin Zayd who narrated this from Ayyub, and he was no more than 30 years of age, he knew this for a whole fifty years, and he knew what the Jahmites and the Mu'tazilah were intending.

And we see that Hammaad bin Zayd (d. 179H) used to say what he had heard from Ayyub as-Sakhtiyaani (d. 131H) as is reported by Imaam ad-Dhahabee, in Mukhtasar al-uluww (p.146):

Sulayman bin Harb said: I heard Hammad bin Zayd (d. 179H) saying: "They are circulating around [the issue of] of wanting to say that there is no deity above the heaven". He means the Jahmiyyah.

So the Salaf walillaahil-hamd were wise to these Jahmites and Mu'tazilites, and all praise is due to Allaah who has preserved His deen through the speech of the pious Salaf.