Immigration policy and sociological policy in Sweden is very complicated and nuanced. For Trump to characterize it as a disaster, without knowing anything about it, is what people took exception to. The problem with discussing the real situation on the ground in Sweden is wrapped in numerous political, sociological and historical layers. I will try to address your points one by one as otherwise it will turn into a maze that will serve no one. This will be a long read:
1) Yes people are disagreeing about what is the actual national opinion on immigration. No surprise there. There are few nations in lock-step on anything. However, whereas it is true that support for the SD, and accompanying stricter controls, has gone up modestly, there is not a wide call to seal borders, but it has triggered a healthy discussion in society which is very beneficial as,
2) Historically party politics in Sweden is little more than a cover for a handful of people to make the most important domestic and foreign policy decisions. Once the King (Gustav V) ceased voluntarily exercising his powers granted through the Constitution in the Act of Succession of 1810 (which was written to accommodate the election of Napoleon's Marshal Jean Baptiste Bernadotte as Crown Prince) in 1918, and officially after the new Instrument of Government of 1974, the Prime Minister and a few chosen cabinet members have exercised most of the executive authority. MPs are selected on party lists and are not analogous to US Reps. They have little input on evens something as big as whether or not Sweden shoo;d develop nuclear weapons. That decision was made by the same six men without consultation over a period of 15 years. This method of governance has led to a rather cloistered decision making process that is often not responsive to the people. This began to change in the 1960s but there is still a fair amount of that still present. As a consequence,
King Carl XVI Gustav and his many hats.
3) The issue of immigration has not been as well debated as in some other nations. As it is not discussed often, this allows fringe elements to shape the narrative and this is how any discussion of policy either devolves to accusations of racism or actual racists trying to inflame opinion. What is true is that the Government still needs wide-spread support for any major policy like immigration and the overwhelming majority of Swedes do support the policy of the past few decades. However, the Syrian crisis is one of a magnitude unseen since the early-1990s when refugees from the Balkans spread through Europe. This has led to a call for, and implementation, to better vetting and stricter border controls. Immigration and asylum policies are now openly discussed widely with input from the electorate. This has changed discourse away from the egg-shell/mass-rape polarization to something more constructive. It should be noted that there still has been no mass shift in opinion or an imminent SD Government being formed. Speaking of the Balkans,
4) The violent crime often cited, that is bomb or grenade attacks in Mälmo, are not conducted by Muslim immigrants but by the Serb and Croat mafia that have entrenched themselves in Sweden since arriving in the 1990s. Like any organized crime syndicates, these folks are hard to root out and I imagine they'll have as much success as the US has had with the Italian or Russian mafia. As for the crime involving Muslims,
5) Assimilation is very difficult in any society; particularly when you don't look like the native population. It usually takes 2-4 generations for full assimilate. Until then, immigrants and their children will always have a hard time getting the great jobs or best housing. That is true of everywhere and the Swedish experience is really little different than any other Western nation (except Norway). Obviously there will be violent malcontents who throw rocks and burn things. I think the difference with the US and Sweden is how law enforcement handles those types of people. Nordic nations tend not to force confrontation and would rather negotiate. It is part of their social DNA as collaborative societies. That said, the notion that entire cities are off-limits and that there are no-go zones is highly exaggerated.
6) So in my view the real question is what is the proper balance to ensure absorption of immigrants in decent numbers while not alienating them or native-Swedes because the job and housing market (housing being a historical problem in Sweden since the 1960s) can't keep up. That is an extremely complex question that is being addressed somewhat successfully considering the level of violence exhibited in other Western European nations is much higher than in Sweden where despite high-profile events like the Megafon people burning cars happen, the crime statistics have not gone up even with the mass influx of the past two years.