Properly speaking the opposite of liberal isn't conservative, it's illiberal. It's perfectly possible for someone to be a liberal conservative, just as its possible for people anywhere along the left right spectrum to be illiberal.

No one in most countries would use a term like small l liberal as a hostile label. In fact even people whose beliefs and practices are extremely illiberal will be likely to adopt the label. And in it's way that is not a bad thing, since it puts at least some limit on nakedly illiberal ideology.

The way it is used in the USA is worrying. It must surely tend to take that limit away, and make it harder for liberal conservatives to speak out. It's a distortion of language which feeds into a distortion of politics.