"I'm choked with emotion and hardly able to speak," the portfolio manager at Janus Capital Management said in an interview with CNBC's "Power Lunch."
"After hawkish talk at Jackson Hole from [Fed Chair] Yellen and [Vice Chair] Stan Fischer, who even said there'd be two hikes in 2016, they've chosen to defer once more a necessary hike to normalize short-term interest rates and provide savers, in my view, with at least a bit of thin gruel to work with to provide for education, retirement and health-care needs."
He believes the contradiction between what Fed officials have said leading up to the meeting and the outcome of the gathering is leaving investors "very confused."
The central bank was sharply divided when it opted to not hike interest rates at its September meeting.
On Tuesday afternoon, Gross predicted through his firm's Twitter account that there was a 50-50 shot the Fed would hike Wednesday.
At its meeting, the Fed also said it now sees rates at 0.6 percent by the end of 2016, instead of the 0.9 percent it forecast in June.
Gross said the lowering of the so-called dot plot is not what financial institutions need.
"They've flattened the curve because now bond markets expect a lower long-term fed fund rate and therefore long-term yields will flatten relative to short-term yields. It's very confusing especially relative to what the Bank of Japan did last night."
All that said, Gross noted the Fed is in uncharted territory now. While it had been model dependent, that isn't working well now and it has become more subjective, he said.
"So they call it data dependent. I think it's more market dependent. In any case, they're in a pickle," Gross said.
He also isn't taking November off the table for a possible hike, even though there is no news conference scheduled.
"Not if they are data dependent and not in my view if they are market dependent and markets move higher into increasingly bubbly type of territory," Gross noted.