You're overgeneralising on the military sales. For starters it are not 'vast quantities' and they certainly do not send quality material to Saudi-Arabia. Most countries aren't even permitting their industries to sell to most middle-eastern countries considering the war SA is waging in Yemen.
And if they send military equipment what they can actually send it 'dumbed down' so much it really doesn't give countries like Saudi Arabia an edge considering what they sell usually only does things that other systems will do just as fine and they'd be able to get their hands on anyway, so it doesn't really matter if it's EU or Russia. And yes, those considerations are political.
To take a small example: Indonesia ordered two sub-destroyer frigates from the Netherlands, from Damen Naval Shipyards, the company that produces Dutch Warships. In cooperation with those, Thales Group basically builds almost all the high-tech radar systems and communications equipment. The ships rank among the top of the world and Thales' radar systems are arguably the best there are. The rest from the higher-tech electronics in Dutch warships is American.
Now, how much does one think Indonesia actually got out of this? A ship that sails, shoots and communicates, sure. But as soon as the order came through the Dutch government intervened and ordere Damen and Thales to basically remove anything that was quality equipment. For example: they got the Goalkeeper system, as in, the machine gun for it, but the radar they actually got with it was so shit it doesn't even come close to the real deal.
It is these kinds of deals between governments and private companies that are usuall signed into law and policy that make it look like a big deal that Saudi Arabia is buying equipment from European companies (which is hard to stop, actually, I mean, it's still a private company) but really doesn't matter that much because European equipment won't be Tsignificantly better than what other countries will offer, and it will certainly not come close to EU military power.