Borussia Dortmund CEO Hans-Joachim Watzke has warned of "an ideological divide in German football" after the German Football League (DFL) voted to keep the 50+1 rule.
The vote, which took place on Thursday, came after a motion tabled by second-tier club St. Pauli.
Under DFL rules, clubs in Germany are not allowed into the upper two tiers if commercial investors have more than a 49 percent stake.
The rule, introduced in 1998, guards German clubs against takeovers and, in theory, ensures that they remain fan-owned.
Eighteen of the 36 clubs from the two upper tiers, including Dortmund, voted to retain it with only four, among them Bayern Munich and RB Leipzig, voting against.
On Monday, Munich CEO Karl-Heinz Rummenigge hit out at the decision and called those backing retention of the rule "ideologists and nostalgists."
But Watzke said: "We must be careful to not attack those who have another opinion, even more so if that's a majority opinion.
"We must be careful that we don't divide the Bundesliga like German society right now is beginning to be divided. We must learn how to argue with respect."
Watzke called Bundesliga clubs "a cultural asset" and said they should not be sold to foreign investors.
"Once that's in China, we won't get it back, and investments rarely run as smoothly as at Paris [Saint-Germain] or Manchester [City]," he added. "Most of the time, they just fail.
"I have the feeling that there is a dangerous tendency in German football right now, and the fans are fighting it.
"Let's look at over-commercialisation, Monday night games, transfer fees, players on strikes. Some of those things also annoy me.
"There's a load of social dynamite in it. We [Dortmund] have 153,000 members, and I know that most of them want to keep 50+1. Should we decide over their heads?
"Things would just blow up in our faces because, once investors have control, those people will not see any fans -- only customers.
"That's why I am deeply worried about a complete ideological divide in German football."