Yeah i guess it’s because they are liberals, French liberals see in America the revoution against the monarchy and pro democracy, they gloss over the slaveowning part and the convoluted system making US democracy a farce - that was also really common in the epoch, USA is basically the only country that wasn’t outright hostile for various shades of French revolutionaries so they routinely escaped there, especially the more opportunist ones like Lafayette or Talleyrand, so US got good press, but really only compared to outright hostile countries like England or Austria.

While US liberals are really antidemocratic, for them the French republic was always way too progressive.