> ... Gmail strips the BCC recipient(s) from messages. The message is sent to the BCC recipient, but the BCC recipient is not displayed in the saved sent message. (The BCC recipient is also not displayed on Gmail's web-based interface if the message originated in Thunderbird.)
This could be the case, but I do not know any of these people, their names and emails are nothing like mine, and all of these emails are not spam, just people talking to each other about home repairs or the latest one was a LinkedIn Password reset email.
> ... Gmail strips the BCC recipient(s) from messages. The message is sent to the BCC recipient, but the BCC recipient is not displayed in the saved sent message. (The BCC recipient is also not displayed on Gmail's web-based interface if the message originated in Thunderbird.)
https://support.mozilla.org/en-US/kb/thunderbird-and-gmail