Your argument doesn't hold because they have reasonable reasons for disallowing botting/scraping.
That phrase is boilerplate in almost any TOS.
The reason is to stop automated "attacks" using scripts. (attacks from the company's perspective, since it is bogging down their web servers, or driving their hosting bill over the moon). When novices write a "bot", this can happen all too easily - they don't think about pacing, and maul the server with dozens of requests per second.
Generally when a seller on a marketplace has a need to access a lot of data, the marketplace provides an API expressly for that purpose. This is vastly more efficient, since the server only needs to provide the raw data, not all the features and presentation needed for a proper web page, which is wasted on a bot.
Given their branding, they might not want partners who need to use automated listings
Jane is a curated marketplace with more than 2,000 shops plus big brands and designer names.
That is how Jane holds themselves out in the marketplace. So it would be consistent with their branding to want their "2000 shops" to actually be small artisanal shops - mom and pop operations. They may take the view that shops which depend on automation are probably not a good fit for the site.
Indeed, Etsy, a craftsman artisan marketplace, has had huge problems with their site being flooded with cheap factory/sweatshop items made to look handcrafted. When 100 different sellers all sell the identical item, or when you can find it on Amazon for half the price or Alibaba for 1/10, well, that is destroying their brand.
This a natural "rivalry of interests" between marketplaces who want to stand out as unique, and sellers like you OP, who want to put the same items in every marketplace.
The prohibition on scraping, conspicuous lack of API, and unwillingness to negotiate are evidence of that kind of brand defense.
Do they have a right to make themselves unique and special? Unquestionably. You would get taken to school on that point, if you sued for a "right" to list and a "right" to use automated means owing to your large number of items.