I would rather have the ability to do it rather than not on pure ideological grounds,furthermore not banning it incentivises transparency, you can see more of where the money is coming from for example in US democrats are funded by more aggregate donors.
Ah, yes, transparency. "I received 250000€ from Renault-Nissan. No particular reason no. They just really like me. We talked. Also please don't pay attention to my upcoming votes and law proposals".
Lobbying is corruption, and it's also pay to play. Noone gets anything good out of it.