To begin with, removing an application from the dock does not completely remove it from your Mac; you can still see the application on your Launchpad. Second, only apps downloaded from the App Store will have a "delete button" when the Option key is held down. Finally, some applications cannot be uninstalled because they are installed as part of the operating system on your device. However, if you want to uninstall a third-party application, I would like give iBoysoft MagicMenu a recommendation.
Except for dragging and dropping apps to Trash, you can also uninstall apps on Mac with Finder, Launchpad, Terminal, the app's built-in uninstaller, and a third-party uninstaller for Mac such as iBoysoft MagicMenu. Before you uninstall apps on Mac, you should make sure the app is not in use, otherwise, you may receive the message "The item can't be“moved to the Trash because it's open."
Free download and install iBoysoft MagicMenu to your Mac to delete unwanted apps right now!
After deleting the unwanted app, you'd better continue to remove its leftover files, so that you can free up more disk space on your Mac. iBoysoft DiskGeeker, the all-in-one disk management tool for Mac, would be a helper. It can scan the Mac hard drive and search for unneeded files, then you can remove them with ease.