How can you make this claim when Frederick Bastiat was a contemporary of Dejacque's? Many of today's leading libertarian-minded thinkers (Thomas Sowell, Walter Williams, etc.) consider Bastiat core to their beliefs and you can hear Bastiat's writings echoed in their works.
Libertarianism as such was founded as a rejection of "moderate" anarchism, and a more extensive rejection of authority than that of Proudhon, along with an absolute rejection of property rights as oppressive.
That he was later adopted by some right-wing libertarians does not mean he invented libertarianism. Many people toyed with similar ideas. Dejacque was the person who gave it a name and promoted it as an explicit ideology.
You'll also not that Bastiat did not take things nearly as far as Dejacque did. E.g. Bastiat argued in Justice and Fraternity even for limited state provided welfare, so he did not even go as far as many right-libertarians. But whatever the size, he argues for a state, not the total dismantling of the state, which was the origin of libertarianism.
As such, Bastiat looks libertarian to right-libertarians because they took left-wing libertarianism and gutted the commitment to liberty of Dejacque to add in state restrictions on liberty to enable property, and in doing so shifted the ideology far to the right. But he's far less libertarian by its original definition than e.g. an anarchist like Proudhon. To left-libertarians he's just another statist.
[1] https://theanarchistlibrary.org/library/joseph-dejacque-on-t...
I don't recall reading anything like state provided welfare in Justice and Fraternity. It has been a very long time since I've read it, but that sounds antithetical to some of his other writings which I've re-read more recently. I would be curious to see the specific passage.
To my knowledge, communal arrangements (like Dejacque seemingly favors) have not proven practical outside of relatively small communities.
He was an anarcho-communist and the first publisher of libertarian political texts.
Right-wing libertarianism is about a century younger, and e.g. people like Rothbard very intentionally tried to find common ground between what he saw as the anti-authoritarian parts of the left and the right, but was largely rebuffed by the left, where left-libertarians, many of whom are anarchists, saw the right-libertarian obsession with property rights as fundamentally incompatible with the goal of maximising liberty.