All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
Your question is very clear. The answer is that Shaykh Ibn Baaz was not the only one who held this view; rather, it is a view that corresponds to the Hanbali School, who say that it is permissible to sit for rest (Jilsat-ul-Istiraahah) (when getting up from the prostration of a Rak'ah [unit of prayer] to start the next Rak’ah) as some scholars of the Hanbali School are of the view that it is prescribed. Most of those Hanbali scholars who are of the view that it is prescribed say that a person uses his feet as support to get up, not his hands.
Al-Insaaf reads:
“It was reported from Imaam Ahmad that the worshiper sits for Jilsat-ul-Istiraahah; this view was chosen by Abu Bakr Abdul ‘Azeez and Al-Khallaal, and he said that Ahmad withdrew his first opinion, and he (the author) authoritatively asserted his second opinion (that Jilsat-ul-Istiraahah is prescribed) in Al-Ifaadaat, and he favored this view in Ar-Ri’aayatayn and in Al-Haawi As-Sagheer, and he mentioned both views without favoring either of them in Al-Hidaayah, Al-Muthhab, Masbook Ath-Thahab, At-Talkhees, and Sharh Al-Majd. It was also said: the one who sits for Jilsat-ul-Istiraahah is the person who is weak; this is the view chosen by Al-Qaadhi, Al-Musannif (i.e. Ibn Qudaamah), and others … Hence, when a person stands, he does not support himself with his hands according to the sounder opinion; rather, he stands relying on his feet and using his knees for support. Al-Aajurri chose the view that one uses his hands for support when he stands up.”
Based on the above, the statement of the Shaykh (Ibn Baaz) is a considered view in the Hanbali School, and it is not a new view.
Allaah knows best.