That's quite easy to explain. They don't have a problem because the people that contract them do it explicitly to run GPUs. They don't have to protect a massive number of people that don't exactly know what they are hiring.
But I wonder more about, say a fraudster using stolen credit cards or gift card abuse, to open an account, or abuse a free trial, and if Lambda Labs makes it super easy and low friction to start up a GPU, then the fraudster can open an account, mine crypto immediately, rack up as much crypto as they can for days or a month until billing fails or trial expires, and just try to squeeze Lambda for as much computing power as they can subject to Lambda’s ability to detect fraud.
Low friction for customers, usually translates directly to higher risk of abuse. AWS adds its limits and friction for a reason, not because they enjoy making life harder (esp. since, easier for customers == more business/revenue).