Marcus Porcius Cato, called the Younger to distinguish him from his grandfather, Marcus Porcius Cato the Elder, is not an easy man to like, a grim and dour personality, but has been one that is admired. That was the case while he was alive and has remained true through the centuries since his death.
It seems that he is more fortunate in his reputation than his censorious grandfather who, although he had a distinguished military career and also one as a senator and consul, is remembered primarily for a treatise he wrote on agriculture and for declaiming, after every speech he made in the Senate, that "Carthage must be destroyed." It was destroyed eventually, in part due to his relentless urging. Grandpa Cato wasn't a likeable fellow either, but was revered by his grandson as a representative of old Roman virtues, unlike the foppish patron of Greeks, Scipio Africanus, who was one of the targets of Grandpa's vindictive style of conservatism.
Cato the Younger was noted for his adherence to Stoic philosophy, and so it's difficult for an aspiring Stoic to be critical of him. I'm critical of him nonetheless, but not entirely so. Even his ally against Caesar, Cicero, was critical of him at times, for good reason. Though Cicero admired the Stoics, he wasn't above ridiculing them and Cato for their extremes--at least as part of a case, in the course of advocacy. Cicero was a lawyer, after all.
Cicero also was critical of him for his obstinacy and refusal to compromise. But Cicero admired him as have many others for his refusal to submit to Caesar's rule of the Roman Republic, soon to be the Roman Empire. When Caesar portrayed Cato as a drunk in his triumph after his victory over Pompey and the optimates, Cicero responded with a kind of panegyric in his praise. Caesar found it necessary to reply to it; Caesar was never able to forgive Cato as he forgave many others, even after Cato's suicide to avoid submission--perhaps even because of it.
Cato is admired as a hero in the ongoing battle against tyranny. He was admired as such by the Founding Fathers of our Republic, all of whom looked to Rome in its creation.
Cato's commitment to freedom, however, is more accurately seen as a commitment to custom and Roman traditional virtues and institutions (the mos maiorum). Individual rights and freedoms were not a concern to Roman government or society generally. Romans, at least traditional Romans, served the state, not themselves. Romans were not libertarians; Cato certainly wasn't one. Cato wanted Rome to be ruled as it had been; by an oligarchy making up the Senate, with some powers held by the plebs and their tribunes as created over time. Rule by one man or a few by virtue of their control of the legions and catering to the people is what Cato fought against.
I have no reason to doubt Cato's commitment to Stoicism, but it strikes me that his very ostentatious displays (walking barefoot, wearing a simple coarse tunic), railing against clothing and conduct which was not similarly rustic and simple, isn't Stoic. It's posturing and prideful. No doubt it had a political purpose and was a kind of propaganda. But it reflects a concern with what should be indifferent, with appearances--with impressing others. Living simply, foregoing luxury is appropriate, but vocally condemning those who do otherwise doesn't seem to me to be something advocated by the Stoics. Perhaps Cato, in this, was more Cynic than Stoic. Diogenes enjoyed flaunting his simplicity, much to the annoyance of Plato. But nobody doubted the honesty and integrity of Cato, not even his enemies.
I think what can be doubted was his wisdom--his practical wisdom, in any case. There is an argument that his refusal to compromise in any respect played a part in ending the Republic and creating the principate. And certain warnings are self-fulfilling. Political and military chaos creates opportunities for the ambitious, and Cato contributed to the chaos, and perhaps even invited it.
Those interested in Cato may want to read Rome's Last Citizen: The Life and Legacy of Cato, Mortal Enemy of Caesar, an interesting book written by Rob Goodman and Jimmy Soni, which I plug here despite their annoying use of diminutives in their names.