Do we think Tesla's objections to collective bargaining are cultural or practical? That is, do they just object on principle or do they feel it would be too harmful to their business?
Cultural. Many American companies think they can skip unions and/or collective bargaining when they come to Europe, and find out to their detriment that they can't.
The Tesla workers in Sweden don't want to unionize. The majority of the ~120 employees in Sweden are ignoring the strike called by IF Metall and continuing to work. Only a handful are supporting the strike.
Elon Musk is known to fire people that support unions openly. I very much doubt they will tell the whole truth if asked, unless it is personally by a friend, not by a newspaper.
I am not sure what the term "boycott" means in this context, but it seems the thing has now escalated from Sweden to Denmark and is about to escalate also to Norway.
Fellesforbundet is now announcing a boycott that will target the transport of cars to the Swedish market if the contractual relationship in Tesla AB is not in place by 20 December.
Fellesforbundet, literally "joint union", is the largest trade union in Norway in the private sector.