Well, this is caused by the fact that Gmail detects Chrome browser and ignores global browser setting which results in converting all email addresses by injecting
mailto: address before each of them.
email@example.com is converted to
mailto:firstname.lastname@example.org and therefore clicking on such address defaults to open compose window. Manually removing
mailto: part from source code fixes the issue and further right clicking won't trigger the opening of compose window.
Therefore, a solution would be to find some Chrome extension which is able to edit source code upon website load and remove all instances of
Another solution would be not clicking on an email address you want to copy, but highlight it with a mouse cursor and hitting CTRL + C
If you are with administrator access, this article states that
mailto: scheme can be globally blacklisted: https://www.chromium.org/administrators/url-blacklist-filter-format
In other instances (outside of gmail.com) you need to delete Gmail from handlers at
chrome://settings/handlers (but as already mentioned this won't work when on Gmail in Chrome)