Thailand endures a complex relationship with corruption characterised by weak governance, opaque webs of political patronage and an expectation of under-the-table payments to get things done.
Demonstrators trying to rid the country of Thaksin's influence by ousting the government led by his sister Yingluck Shinawatra believe he has broken the kingdom's tacit contract with graft, says political commentator Voranai Vanijaka of the Bangkok Post.
"Thai people are quite pragmatic... we understand that everybody takes a little bite of the apple," he told AFP.
"The problem with Thaksin is that he put a sign on the whole apple tree saying 'property of the Shinawatra family'... that's dangerous to do here."
The demonstrators allege Yingluck is being controlled by her brother, a tycoon-turned-politician who was ousted in a 2006 coup and lives overseas to avoid a jail term for abuse of power that he says was politically motivated.
Protesters point to accusations of wrongdoing over the former leader's business empire, as well as complaints about populist policies and alleged "vote buying" that they say explain the victories of Thaksin and his allies at every election since the start of this century.
"Thaksin has taken too much and his big mistake is that he has made it open for everyone to see," said rally supporter Rocky, 24, on the fringes of a march through an upmarket Bangkok neighbourhood last week.
Rally leaders have harnessed that indignation to package their fight as an anti-graft crusade, while urging the military and independent institutions to aid them in their attempt to block February 2 elections that Yingluck is again expected to win.
Thaksin is adored in the northern heartlands and among the urban working class, but is loathed by many among the Bangkok middle class, southerners and the royalist establishment.
Following his removal from power, the former telecoms baron was sentenced in absentia to two years in jail over a land deal involving his wife.
Then, in 2010, a Thai court confiscated around $1.4 billion - or about half of his fortune - over tax evasion linked to the sale of his telecoms company during his tenure as prime minister.
Thaksin says he is innocent of wrongdoing and the victim of manoeuvering by his political foes.
The protest leaders "use corruption claims to attract the crowd", his legal adviser Noppadon Pattama told AFP, accusing political opponents of trumping up graft claims.
"But to accuse the Shinawatra family of monopolising corruption is wholly unfounded," he added.
Criticism against the former premier has also been directed at so-called "Thaksinomics" - big-spending populist policies including free healthcare, cheap loans and a controversial rice farmer subsidy.
The rice scheme, introduced by Yingluck's government, has drawn particular ire, with claims it engendered widespread corruption and drained Thai coffers of billions of dollars just to shore up the Shinawatras' rural voter base.
Few politicians remain untarnished in the hurly-burly of Thai politics, where the most outspoken politician to campaign against corruption, Chuvit Kamolvisit, is a former massage parlour king who has openly admitted to paying bribes in the past.
Even firebrand anti-government protest leader Suthep Thaugsuban - who is marshalling street rallies aimed at "shutting down" Bangkok that are now stretching into their second week - has faced allegations of corruption in the past.
As a minister for the then-ruling Democrat Party in the mid-90s, Suthep was heavily criticised over the use of a land law which resulted in rich people claiming property meant for the poor. The government dissolved parliament in the fall-out from the scandal.
However, some see Suthep's re-invention as an anti-graft hero as part of a wider public rejection of corruption.
"Suthep is not perfect... but he's changed now he is a leader and he is going to retire anyway after this movement," said 78-year-old protester Amonrat Kridakon. "Thaksin is the problem."
Statistics indicate Thailand has failed to decouple its politics from corruption.
The kingdom ranked 102nd out of 177 countries in Transparency International's latest global index of how corrupt public sectors are perceived to be - level with Moldova and behind the Philippines and India.
And a recent survey by the University of the Thai Chamber of Commerce found that businesses were paying between 25-35 per cent of the value of contracts to grease the palms of government officials, up from 5-10 per cent in 1990.
"Maybe before Thais would pay to get something done faster... there was a 'tradition' of corruption," the university's Thanavath Phonvichai told AFP.
"But the protesters realise that everything needs to change. They can't stand it anymore.".