Sendgrid seems to be used as the infrastructure to send emails from a lot of the email service providers I use. They are not spam companies and react to custome

Sendgrid seems to be used as the infrastructure to send emails from a lot of the email service providers I use. They are not spam companies and react to customers who get marked as spam by suspending accounts and doing reviews. I'm going to guess Sendgrid themselves also look for high ratios of spam reports and do the same.