Answer is easy. To destabilize the west
No different than Soros' aims.... again, hypocritical to criticize receiving money from one source and not all external sources that have a particular agenda contrary to majority voters' desires. I'm sure most Brits don't appreciate their politics being influenced by a person who is known to have 'broken the Bank of England' and continues to manipulate the currency through political inference. Yet that's somehow perceived as not a big deal but donations from Russia are, even though both parties obviously are donating money with the expectation of particular actions that suit their agenda. Otherwise, there is no reason for any person, any state, any group to donate to any politician, group, etc. Hell even donors expect to get a wing or building named after them when donating to hospitals and schools and be immortalized with some bronze plaque or statute.
You're okay with that, I assume?
Personally, I don't care. As long as my house is standing, cash is coming in, I can enjoy a Sunday ride on my Harley and have the ability to raise a family in a socially conservative household and protect myself and those in my home with lethal force I'm good.
Also, I believe in karma and because of that I don't feel any sort of uneasiness in terms of election manipulation. The left blows the US election interference/political manipulation totally out of proportion - Russians purchasing not even a full 6 figures of Facebook and Google ads is somehow a threat to our democracy, a manipulation of our politics and elections, yet accepting millions upon millions from Saudis, Muslim Brotherhood, Soros, etc. isn't? So to criticize people like Farage, Le Pen, Trump, etc. for accepting 'dirty money' without criticizing people like Clintons, Sarkozy, Macron, half the MEPs, etc. for doing the same thing is again, hypocritical.
If the US, France, Germany, UK, etc don't want their elections interfered in, then they shouldn't interfere in the elections and politics of others. Or at the very least they shouldn't be surprised and claim the moral high ground when their politics are interfered with by outside sources after decades of doing the same to them.