Amazon, the notorious industry disruptor, in June shut down its 4-year-old Amazon Restaurants project that delivered plates to Prime members in 20 U.S. cities.
"The bottom line is that Amazon's getting out of the food delivery space — that doesn't change anything," the "Mad Money" host said. "GrubHub's still facing relentless competition. I think it's way too risky to own here."
"I think this development is being blown way out of proportion. Amazon Restaurants was tiny," he added.
GrubHub's shares, which are down more than 30% from where they traded a year ago, rose more than 7% after Amazon pulled the plug on its rival service a little over a month ago. Amazon still has an interest in the delivery space with a stake in U.K.-based Deliveroo.
The stock is up more than $5 per share from its June 11 close, but Cramer sees more headwinds in the future and is not convinced of its long-term viability.
There is loads of competition in the restaurant delivery space — that's good for consumers, but bad for business. Among the public and private companies offering logistics solution between restaurants and hungry customers are Uber Eats, DoorDash, Postmates and Square-subsidiary Caviar.
GrubHub's margins have been "under serious pressure," Cramer said.
"The company's been spending money like crazy to defend its market share, and their efforts ... haven't been all that successful," he said. "Frankly, you can read Amazon's decision ... as an indictment of the whole industry."
Cowen analyst Thomas Champion has a different view than the "Mad Money" host. He thinks GrubHub could become a potential buyout target for Amazon in the future.
CEO Matt Maloney appeared on "Mad Money" in April, where he assured shareholders that GrubHub's advertising investments will unleash the "lifetime value of your customer. Once they start ordering, we know that they're lifers."
Earlier this week, however, Domino's Pizza CEO Ritch Allison questioned if delivery apps like GrubHub are sustainable. He conceded that delivery competition put a dent in second-quarter pizza sales before telling Cramer that investors are subsidizing low delivery prices to take unprofitable market share.
"We don't know how that's going to shake out once consumers actually have to pay the full cost of that delivery because those fees are quite substantial, relative to the cost of the underlying food," Allison said at the time. "I think we also have not yet seen what's going to happen with the supply of restaurants on these platforms as well."
On Friday's show, Cramer noted that the New York State Liquor Authority laid out new rules that could impact how GrubHub charges restaurants usage fees. GrubHub's pricing structure, while negotiable, can cost food partners about a 20% marketing commission, a 10% delivery commission and a 3% processing fee on each order, CNBC reported.
If regulations are on the horizon, that may have an uncertain impact how delivery companies make money.
"Back in February, I told you to run, don't walk, away from GrubHub as well as all of its publicly-traded competitors," Cramer said. "Sometimes an industry will be booming, like this one, but there's no real good way to invest in it."
GrubHub is scheduled to report second quarter earnings at the end of the month.
Disclosure: Cramer's charitable trust owns shares of Amazon.