The phrase "a passionate case of" is correct and usable in written English.
It can be used to describe a strong or intense situation or feeling related to a particular subject or issue.
Example: "She presented a passionate case of environmental conservation during the conference, urging everyone to take action."
Alternatives: "a fervent argument for" or "an ardent plea for".
And, according to sources, he is now calling his friends in the Senate, making a passionate case on behalf of the cancer research funding that is contained within the 21st Century Cures legislation.
In his book Microbes and Man (1969, now in its fourth edition), Postgate made a passionate case for the importance of micro-organisms.
The adept biographer Meryle Secrest begins "Modigliani: A Life" (Knopf; $35) strategically, making a passionate case for the art of an illustriously self-destructive painter whose prestige, as I see it, rests more on his perennial appeal to sensitive adolescents than on grownup critical favor.
Read Xan Brooks' review from Venice With a subversive wit and charm, the Mali-born director Abderrahmane Sissako dramatises the Islamist takeover of Timbuktu in 2012 and mocks the pomposity and aggression of the militants — making a passionate case for the neglected Islamic traditions of humanity and tolerance.
Roberto Ridolfi's landmark biography, of 1954, made a passionate case for its subject's Italian warmth of spirit.
In a first-person article on Medium entitled, Why It's Time We Paid Employees to Exercise at Work, Holmes makes a passionate case for exercise becoming part of the working day and bosses paying for it.
10.44pm: Surallun makes a passionate case for these bunch being some of the most brilliant, fiery business minds in the history of business.
Where else could a citizen lobby called Hookers 4 Hillary, five hundred strong, make a passionate case for Obamacare and the virtues of imposing higher income taxes on their boss, the owner of a brothel called the Moonlite Bunny Ranch?
When the Guardian reported this week that Theresa May had privately made a passionate case for Britain's continued membership of the EU shortly before the referendum, it didn't look great.
4.30pm BST US senator calls for NSA reform The US senator Ron Wyden has set out a passionate case for reforming the NSA in the wake of Edward Snowden's revelations.
