Until 1989, the corporate tax was 52%. Yes there were various deductions, but still, 52%. Then a wealth tax of 2.5% on assets (all asset classes) over 1.6 million kronor - about $1.5 million in todays monetary value. This wealth tax could also be collected from a corporation when its liquid holdings exceeded double than that that of its debt.
Add to that, a intense political debate about introducing the so called Employee Funds - a mechanism in where a large part of the collected corporate tax would be dedicated to buying shares in the taxed corporation, shares that would then be distributed among the employees with a goal of collective ownership.
Perhaps indicative of the business climate in 1970s Sweden, Astrid Lindgren, the author of Pippi Longstocking, famously wrote a short satirical story about her over 100% margin tax rate. https://en.wikipedia.org/wiki/Pomperipossa_in_Monismania.
Note that Ingvar Kamprad wasn't the only one to leave Sweden for tax related reasons in the 70-80s era. To name a few others: Hans Rausing (TetraPak), Stefan Persson (H&M), Ingmar Bergman, Björn Borg..
Essentially, there's an important and material difference between saying, "I'm a socialist, but these taxes, which I'll continue to pay, are excessive" and "I'm an unreprentant fascist who must hide my wealth from these undeserving thieves," even if the latter can opportunistically profit from the former's sentiment to justify their own actions.
That is a really interesting idea.