Last season, Dortmund had led the table for much of the campaign before a poor run of form in the opening months of 2019 saw them eventually miss out to Bayern Munich on the final day of the campaign.
Having held a nine-point lead at one stage, missing out on the title in such a way led to question marks over the Dortmund players' mentality -- and that issue has resurfaced following the draw in Frankfurt. But Reus said this is just an easy excuse.
"Honestly, that mentality s--- you keep talking about, it's just a pain in the ass," Reus said after the match. "Is that all you come up with?
"That the 2-2 was a mentality problem? We were stupid, of course, but just don't mention that mentality s---. The same s--- week in, week out."
Dortmund twice took the lead through goals from Axel Witsel and later Jadon Sancho in Frankfurt but Andre Silva had equalised at 1-1 and later a Thomas Delaney own goal gave the hosts a share of the points.
The draw came two Bundesliga matches after their disappointing 3-1 defeat away to newly-promoted Union Berlin.
Dortmund sit third in the table behind Bayern and leaders RB Leipzig.