Earlier quoted context omitted.
Transferring a domain costs money (although not much); more importantly, it causes the domain to be renewed for an extra year. If the owner of the trademark doesn't want the domain to exist (e.g, if it's some off-brand use of their mark), having the domain transferred to them is counterproductive.
Just trying to understand this. Wouldn't that actually be good? Wouldn't the trademark owner want the domain so they could keep it unassigned? If they let it expire, someone could eventually purchase it and use it for similar purposes. That seems counterproductive to me, not transferring it.
Consider a low-quality domain name like "buy-acme-widgets-cheap-123.com" (for the trademark "Acme"). There are so many possible domain names of that form that Acme Co. would have no real interest in trying to protect that specific one from being misused in the future.
Another messy situation would be if the domain name contained multiple trademarks belonging to different owners. The holder of one trademark would probably be reluctant to take ownership of a domain name which also infringed on another company's trademark!