All in the same net

My neighbour is fun. He often has pretty birds flying by. However, he doesn't cause any trouble and respects the people in the building. It seems to me that he drinks with his wife and, if the occasion permits, he makes ends meet. I was surprised to learn that he had been sentenced like a big fish, even though his case seemed rather harmless. Could the price of criminal sentences also be staggering?
Xav, Meyrin

A succession of minor offences can lead to a major conviction.
Drugs
Under Swiss law, the Narcotics Law (LStup) punishes the use, possession and, above all, trafficking of drugs, with a severity that varies according to the seriousness of the offence. The accumulation of small quantities of drugs sold or exchanged can be enough to qualify an offence as a "serious case" if the total exceeds a threshold set by case law. So it's not the size of each transaction that counts, but its cumulative effect.
Our Federal Court has ruled, for example, that when an individual regularly resells small quantities of cocaine, it is not enough to examine each sale in isolation. Even if no single transaction crosses the red line - which is set differently depending on the drug in question - the sum of them can demonstrate a risk to the health of a large number of people, which is enough to constitute a serious case under Article 19(2)(a) LStup. This is the case even if the sales are made at different times, in different places and without any apparent coordination. The law applicable in this case favours an overall interpretation of the facts, taking into account both the total volume and the awareness that the perpetrator may have had of the collective danger caused by his actions.
Traffic
In the case you cite, the criminal authorities probably considered that, even if the quantities involved in each exchange appeared to some to be insignificant and the atmosphere in your neighbour's home seemed convivial, the acts as a whole revealed sufficiently significant trafficking activity to justify a severe classification. The fact that he also consumes as a couple or that his customers are passing through does not protect him from being convicted if all his actions exceed the tolerated thresholds.
Such a decision may surprise you in its rigour, but it is the result of a fair application of the criterion of endangering health, which naturally does not take into account the pleasant and discreet character of the person concerned! On the contrary, it is part of the Swiss justice system's determination to discourage repeated micro-trafficking, which, when put together, feeds the black market and its health consequences.
In short, even small fish can end up in the net of justice if they swim too often in the same murky waters.