A small local gym is not “a corporation”.
In any case, predatory/scammy practices are bad no matter what the ownership structure is. Being small and local doesn't excuse you from abusive behavior.
There are four general types of corporations in the United States: a sole proprietorship, a Limited Liability Company (LLC), an S-Corporation (S-Corp), and a C-Corporation (C-Corp).
People who whine about corporations fail to realize that 99% of the businesses they deal with everyday are incorporated entities under the law. Your pizza shop, tanning salon, dentist, ice cream shop, sandwich truck...
A business entity can be a good or bad actor. Their legal status as a corporation does not mean they are automatically bad, regardless of the size or public/private status. Their actions and policies define them as either good or bad.
Words have meaning and they should be used appropriately.
Corporations generally have more diffuse ownership than LLCs, which is why people ascribe bad things to that specific type of entity. If there is a gym doing these tactics, and it's an LLC with a handful of owners ("members"), those owners are just asshole humans that could theoretically be punched in the face. Whereas if it's a corporation with diffuse ownership, then the policies become "just business" and "nobody's fault".
Although corporations certainly can be "closely held" by a few people or a family, just as you can sell shares in an LLC to investors at arms length or have all/part of the LLC owned by a corporation or business trust.
And frankly I'm surprised by the number of small businesses I see set up as a sole proprietorship or partnership and doing-business-as rather than spending the money on LLC registration fees. Although as a business gets smaller the protection created by the LLC structure also shrinks, so it's somewhat understandable.