Ariane Espace isn't the ESA. The ESA put money into the Ariane program, it's not the same. Ariane Espace is a French commercial company with many links to ESA, but its primary mission is to ensure France's civil and military access to space. This has been extended to other European countries, but France holds more than 60% of the shares, the launch site, the transport and assembly infrastructure, and is responsible for the defence of the site, etc.

https://en.wikipedia.org/wiki/Arianespace

The French government wanted a reliable way of sending heavy observation satellites into geostationary orbit. This explains many of Ariane's design choices. Civil and commercial activity are just extra or bonus way of cutting costs.

For example, one of Ariane lesser-known activities is to produce ballistic missiles for the French strike force.

https://en.wikipedia.org/wiki/M51_(missile)

Good answer, the european space program is just a spinoff of the french ICBM program nothing else; it also explains the reluctance of other countries to finance it, like anything approaching the french military industry, because you know french are imperialistic, I known, I'm french \s.

Imperialism, I call that General de Gaulle's France! Anyone who says otherwise is a traitor to the homeland, American or Russian bootlickers! \s

More seriously, France often has a non-aligned or sovereign vision of its programmes, which makes many European countries uncomfortable, as they don't really want to assert any form of independence from the USA.