Sid,
You have confused a number of different things.
After his retirement from the Reichswehr in 1932, Hausser joined the Stahlhelm which was a right-wing nationalist veterans organisation. From that fact, we may deduce that Hausser was a supporter of German nationalism, which was a very common position for German military officers. The Stahlhelm differed from the NSDAP in that it was monarchist.
Here are some details of how the Stahlhelm was merged with the SA in 1934:
https://en.wikipedia.org/wiki/Stahlhelm ... ntsoldaten
After the Nazi seizure of power on 30 January 1933, the new authorities urged for a merge into the party's Sturmabteilung (SA) paramilitary organization. Franz Seldte [the head of the Stahlhelm] joined the Hitler Cabinet as Reich Minister for Labour, prevailing against Duesterberg, who had already come running for his swearing-in. The Stahlhelm still tried to keep its distance from the Nazis, and in the run-up to the German federal election of 5 March 1933 formed the united conservative "Black-White-Red Struggle Front" (Kampffront Schwarz-Weiß-Rot) with the DNVP and the Agricultural League, reaching 8% of the votes. On 27 March 1933 a SA raid with the intention of disarmament on Stahlhelm members in Braunschweig, who under the command of Werner Schrader had forged an alliance with scattered Republican Reichsbanner forces. The violent incident initiated by Nazi Minister Dietrich Klagges and later called Stahlhelm Putsch was characteristic of the pressure applied by the Nazis on the Stahlhelm in this period, mistrusting the organization due to its fundamentally monarchist character. In April Seldte applied for membership in the NSDAP and also joined the SA, from August 1933 in the rank of an Obergruppenführer.
On 27 April 1933, Seldte had officially declared the Stahlhelm subordinate to Hitler's command. The attempts by the Nazis to integrate the Stahlhelm succeeded in 1934 in the course of the "voluntary" Gleichschaltung process: the organization was renamed Nationalsozialistischer Deutscher Frontkämpferbund (League of National Socialist Frontline-Fighters) while large parts were merged into the SA as Wehrstahlhelm, Reserve I and Reserve II contingents. The remaining Frontkämpferbund veterans' units were finally dissolved by decree of Adolf Hitler on 7 November 1935. Seldte's rival Duesterberg was interned at Dachau concentration camp upon the Night of the Long Knives at the beginning of July 1934, but released soon after.
It is obvious that the merger of the Stahlhelm with the SA was not achieved by a free vote of all its members, but by a deal between Seldte and Hitler. Hausser became a member of the SA by reason of the fact that an organisation to which he belonged was more or less compulsorily absorbed into it; we cannot assume that he wanted to become a member of the SA, or that his membership in it indicated his support for all elements of National Socialist ideology.
Thus, your claim that Hausser was an "ideological Nazi" is a prejudice on your part, unsupported by impartial evidence, derived from your prejudicial view that all senior officers of the Waffen-SS must have been fanatical National Socialists by definition.
Nothing in Hausser's career shows him as joining any National Socialist political organisation out of ideological conviction. The only organisation he joined voluntarily after his retirement from the Reichswehr was the Stahlhelm. The only reason he ended up in a paramilitary organisation linked to and controlled by the NSDAP, namely the SA, was that the Stahlhelm was absorbed by that organisation.
We cannot know whether or not he would have voluntarily joined any organisation linked to the NSDAP if the Stahlhelm had not been absorbed into the SA. The fact that he joined the NSDAP fairly late, three years after he had become a member of the SA through absorption rather than through voluntary enlistment, and after over a million persons had already joined it, suggests that he was not driven by an ideological commitment to National Socialism.
As I wrote previously, Hausser probably agreed with many elements of National Socialist ideology, but that is because those particular elements were common to all variants of German nationalism, eg the concept of a Greater Germany incorporating all territories with an ethnic German population, or which had been part of the German Reich in the past. His agreement with those particular elements does not mean that he was a genocidal maniac, and nothing in his career in the Waffen-SS suggests that he was.