This is not necessarily the case. For example, the Shafi'i school of jurispudence deems all liquid intoxicants are impure (as in, physically) and impermissible to trade in regardless of source. The only path to purity is turning say wine into vinegar (though there is some nuance here). This school has a very rich history and has existed far long before ibn 'Abd al-Wahhab was born and is followed by the majority of Muslims in south east Asia, Jordan and parts of the Levant, Kurdistan, the Caucasus, Somalia, and other places.
Due to the prevalence of liquid intoxicants in modern manufacturing and the world at large, sometimes scholars of this school deem the presence of intoxicants in certain products excusable to use under certain conditions. This is according to pre-existing principles regarding difficulty, need, etc. (rather than "clergymen making things up").
As a side note, amongst "Wahhabis", jurispudence is not universal, unlike theology. For example, you can find people who may be called a "Shafi'i Wahhabi", i.e., a Wahhabi that follows the Shafi'i school of jurispudence. Though the term Wahhabi isn't typically appreciated by them. There is a style of jurispudence that is mostly popular amongst them (and not most other Muslims), however it is does not necessarily lead to "harsh" or strict views that outsiders assume of them.