I don't know about "most", maybe true maybe not, but definitely not all. However, you live in Western Europe, where nationalism has been curbed even on the right, and where many far-right parties are also tax-cut populists. Further East and Southeast, you'll find lots of conservative parties that preach the community of the nation, and solidarity with fellow members of it. Even if these parties usually represent one elite or another that provately looks down on the masses of co-nationals and pursues economic policies hurting them. What was different from left-wing solidarity is the exclusivism: no solidarity with non-nationals or those branded traitor, and the prime occasion for a show of solidarity is in a nationalist conflict with other nationals.

I also note that in Poland, it's in the name: the present hard-right parties grew out of Solidarność.

Even for most West European conservative parties, the concept of national solidarity used to be a main theme in some form, and residual traces remain (f.e. even though German Christians believe in charity, too, the welfare state was started in Germany under the conservative Bismarck).

_{*Lunatic*, n.
One whose delusions are out of fashion.}