"Tariffs don't affect exporters"
Really? So why exporters are so worried about tariffs? How could tariffs affect importers and not exporters - which are tightly coupled?
Tariffs do affect exporters as well importers - they could sell less because of higher prices, or have to accept to offset some of the tariffs with reduced profits to keep market share. Who have to sustain the major burden depend on who the exporter and importer are and their relative strength in settings buy and sale prices - and often it could be simply the exporter local branch.
If it affected only the importer - who would care if Trump or Biden sets a 1000% tariff on foreign goods or services? They would be the perfect tax, exporter would keep on making money and local buyers will happily pay the tax while buying as much as before... in which universe that happens?
This lack of economics basics do well explain why some ideas are acceptable to some voters.