No, that isn't OK.

"Spam" is a term used for unwanted or bulk email. Please explain what you mean by "hijack" and "spam me".

And, specifically which two add-ons are doing that? URL of those add-ons on the Addons.Mozilla.Org website would be helpful in identifying the 'culprits'.

There are some legitimate extensions that, every time you update them, show you a page about the update: release notes, new features, or other news. That's not unusual, although it may be annoying.

Some e-mail providers have an option to sort incoming mail. Check with your provider.

Go here and register for protection for your e-mail and phones; The National Do Not Call Registry

the-edmeister said

No, that isn't OK. "Spam" is a term used for unwanted or bulk email. Please explain what you mean by "hijack" and "spam me". And, specifically which two add-ons are doing that? URL of those add-ons on the Addons.Mozilla.Org website would be helpful in identifying the 'culprits'.

Video DownloadHelper does it all the time! Some others do too.