I agree that as a blanket statement “gzip is enough” is not technically correct, but I think it’s largely correct in spirit, in that people tend to reach for minification by default, without really thinking about what they’re gaining.
If minifying saves you 200 KB overall, for example, and you expect your average user to have a 200 Mbps connection, you’re saving a grand total of 8 ms on page load, which is an imperceptible difference on its own. In exchange, you’re getting worse debugging, and worse error reporting.