It is the nature of the corruption.
Typical MO for GOP flavor corruption, is "In-crowd gets first dibs". This is in line with their US-Them descision making. This MO is part and parcel with the party's politics. "Party of NO", and all that. (If decision != origin_GOP then answer == "NO", regardless of other values in play. To whit, the horror that is the ACA. How hard exactly did they fight this thing, despite it being a veritable clone of a prior GOP proposal? So hard they almost defaulted the country? Yeah-- that's how strong the party line ties to ideology, and not the business.) Corruption issues surrounding the GOP and its individual members tend to focus in this area. Eg, look at the recent Christie scandal: Mayor did not comply with lead party member, lead party member uses corruption to send message. The major theme again, "not for, thus against, any tactic to stop the against authorised, legal or not." This theme carries over all over the damned place with the GOP and the organisations it created/exanded/empowered, such as the NSA. "Not american, thus enemy, all methods authorised, legal or not." (And recently "Not nationalistic enough, thus not american, all methods authorised, legal or not."-- and also with the recent federal court rulings about legality. "Agency == GOP origin; Approve.")
In the vast majority of cases of GOP corruption, the primary focus is on the protection and sustenance of a core group. The "us". At the expense of everyone else "the them". This core group is composed of the leaders of the GOP, who are so deeply programmed by their own koolaid that they honestly do believe that this corruption protects american interests. (Rather, "true" american interests.)
If you compare this with the DNC flavor corruption, they simply favor doing whatever the hell they want in full view of the public to personally enrich themselves, without any moral or ideological imperitive driving this behavior. Eg, you have revolving door regulatory positions with industry lobbyist positions, former lobbyist justices, and co. There is no overriding ideological feature to combine and unify the nature of these corruption instances, in sharp contrast to that of the GOP.-- or if there is one, I have yet to determine what it is. The primary focus seems to be on staying in power, for the sole purpose of staying in power. Eg, corruption for the sake of being corrupt. The use of an ideological position appears to merely be a cover-- DNC politicians are well known for flipflopping on ideological grounds, in order to stay in office.
(Compare to GOP politicians, who jumped the shark just 2 months ago, and held the whole damned country hostage on ideological grounds-- clearly not bright if the goal is to stay in power.)
It is not that one is more corrupt than the other-- it is the nature and motives behind the corruption.
GOP == party ruled by ideology, that uses corruption.
DNC == Party that is ruled by corruption, that uses ideology.
That is how they are antithetical.