You're right, it's not fair to compare a freelance journalist or writer to some of the influencers and I don't think anyone would argue that a free gift is adequate compensation for a properly researched, professionally written and edited article.
But these influencers have moved the goalposts about what constitutes "content". What used to be say an advertorial in a magazine is now a few instastories. Exposure for a small brand now comes from an influencer rather than a press piece written by a journalist. Brands have jumped on this, shrewdly realizing that if they can get some good coverage for the bare minimum of investment, why wouldn't it be good business to engage in influencer marketing rather than paying a freelancer to write editorial copy. And you only have to see the current use of "press sample" instead of #gifted to realize that some of these influencers are actually trying to insert themselves into a position that they're neither qualified for or entitled to but are jumping on this idea that influencers as content producers are the new wave of journalists and writers. (To be clear, I hate this notion.)
Take a brand like Bobbi Brown, a high end brand that's sold at counters, part of Estee Lauder with a marketing budget surely in the millions. Yet they're sending products to instamums who are clearly not the target demographic (nor are their followers), wouldn't part with their own cash for it and don't even do a good job of talking about the products when it's in their hands. Yet it must pay for them else why would they continue to use these influencers as part of their marketing strategy.