We do not agree with Firefox or Google Chrome blocking plugins such as Java or Flash. It seems that Firefox is purposely making it difficult for users to run plugins even after the customers has agreed to enabled them.
Each plugin has its vulnerabilities and in fact, the more powerful the plugin, the more vulnerabilities it will have. To protect themselves against vulnerabilities when browsing, customers should only run programs and plugins from trusted websites.
It is the same issue with emails and attachments or links. Email applications do not block all emails that have attachments. Users can decide what attachments they want to open. They will open attachments from trusted senders. If you install a SPAM filers, there will be options to decide what emails are considered suspicious. Browser should take the same approach and not try to control plugins.