How can bribes from Big Pharma be legal?

I still maintain it is an absolute scandal that Big Pharma pays big bucks to doctors and hospitals as sweeteners (read: bribes) to encourage them to prescribe their drugs. How can that even be legal?
The latest figures show that the 10 largest offenders paid out a total of $76 million to Canadian doctors, hospitals and other healthcare providers in the last year (2018), marginally up from the previous year, with the largest sums coming from Abbvie, Novartis, Amgen, Roche and Merck (but they all do it). Now, it's good that the companies voluntarily disclose this information now - more than they used to do. But shouldn't we be doing something about it, like stopping them, for instance. I'm sure this wouldn't be allowed in other sector of industry. Can you imagine the outcry if the steel industry did this, or the telecom industry. How, then, can the pharmaceutical industry get away with it?