Worst case-scenario for Amazon is that we'll see some kind of stand-off where multiple labor unions prevent their members from working for Amazon, or doing work for Amazon (usually things like truck drivers at other businesses going on strike instead of delivering good to/from Amazon).
But hasn't this already happened with recent reforms regarding the limiting of strike rights [1] and current LAS negotiations.
[1] https://www.arbetaren.se/2019/06/19/riksdagen-klubbade-inskr...
It is abstractly a huge deal and practically a huge deal for Hamnen, SAC, Brandmännens Riksförbund and other alternative unions because it excludes all competition among unions and channels all reform through the internal political workings of those unions like LO/Kommunal. As the a laywer in Arbetaren explained (and others have explained elsewhere) previously, it allows for company (i.e. "yellow") unions which is a realistic problem now considering Amazon is involved.
The ruling Social Democratic Party has strong ties with the unions though.
its the other way around.
Amazon have a pretty good alternative, so they'll only warehouse in Sweden if it makes economic sense vs Germany + Poland. As for the unions, their incentives and alternatives may be different to the union members too.
Generally it's funny how this region (Nordics) is reported in the media as some kinds of rationalist demi-gods, when in reality most politics here are just your regular smokescreen mixed with wishful thinking and a lack of understanding the real world.
In conclusion, politicians will do as politicians do nowerdays - drive their own career over the 'public good'.