I guess much depends on your prior expectations with respect to questions of the degree to which outlaw motorcycle gangs (OMCGs) behave badly. Anyone can say that X is not as bad as I had gathered from popular culture. That does not mean X is not bad, it is merely a statement about your expectations.
There is a clear demarcation to be drawn between OMCGs and perfectly legitimate bike clubs like the BMW owners association. Middle aged lawyers and bankers enjoying the frisson of a walk on the wild side by buying a vintage Triumph or Norton are not what we are talking about here.
Plainly OMCGs are a threat to social order. They have a substantial role in drug distribution, and that leads to turf wars and other forms of violence (such as violence associated with collection of illicit debts). Another key driver of violence is perceived treachery. Drug people are regularly informing police about the operations of their rivals in order to cut out competition.
Recognising that OMCGs are often (but not always) middlemen does not minimise their role. Frequently, middlemen are the biggest players in a chain of distribution. Big supermarket chains are vastly bigger and more significant enterprises than many of their suppliers, for example.
Obviously enough, most of the time OMCG members are occupied with making money, legally or otherwise. Obviously, they recognise that violence and murder are bad for business. But that recognition is only one driver of behaviour. If there were no others, there would never be criminal violence. But there are others - poor impulse control, a certain hypersensitivity to perceived disrespect, and a need to enforce internal political and hierarchical authority are among them.
Even the Economic Man argument about violence being bad for business is countered by other Economic Man arguments. A very cheap alternative to actual violence is merely to credibly threaten violence. Very frequently it has the same effect, and is pretty much cost free. But to maintain the credibility of the threat, it is necessary sometimes to act on it. This is why debtors are sometimes killed for failure to pay, even though it might seem irrational to do so from the perspective that it eliminates the possibility of that particular debt ever being repaid. It is done “to encourage the others”. OMCGs have learned the dual skills of projecting menace and enforcing omertà. If their predominant interests were enjoying bikes and fresh air, why are these things such dominant aspects of their culture?
For the above reasons, most OMCGs are not running about killing other people willy nilly, any more than police kill villains at anything like the rate they appear to in TV shows. But that does not mean there is no violence. Nor does it mean that the fact that most violence is directed to other members of the criminal world make it OK. Even if you accept that it is, the rate at which collateral damage occurs is absolutely unacceptable.
Equally, an attitude of “if you don’t poke the bear you’ll be fine” only serves to enable the general expansion of crime into more and more otherwise legitimate undertakings. It is a Bad Thing socially, economically and in every other way for there to be areas of otherwise legitimate business that legitimate competitors fear to enter because of intimidation. Historically, organised crime starts with marginalised business like tattoo parlours that no-one cares much about, but moves into essential services like garbage collection and transport, by which time it is very difficult to wind back. It seeks to create monopolies. Worse, it has the effect of creating a sense of resignation that menace is simply a tool of business in some sectors of the economy. IMHO, that should be vigorously challenged.
I would expect that there is widespread recognition that OMCG activities like highly publicised delivering of cuddly toys to sick kiddies is quite cynical and manipulative brand management. The mere fact that not every (or even most) interaction with the straight world is associated with violence or menace does not mean anything much. Of course they are capable of being polite on their own terms. It would be impossibly exhausting and distracting to be permanently angry in every interaction. That should not serve to distract from the real threat they represent.
As to enforcement, OMCGs are “hardened targets”. They are neither naive nor passive players in the investigative process. They are among the most difficult organisations to inject an undercover police officer into. The expectation that doing so will result in provably uncovering all the activity of a particular OMCG is optimistic. But the purpose of investigative operations is not just to gain evidence for prosecutions (although that is a dominant purpose), it is to make the environment in which OMCGs operate so hostile to their activities that their capacity to function is severely compromised. Paranoia and the injection of energy into counter-investigation radically reduces their ability to freely undertake unlawful activity.