I’m going to make a best guess based on what you’ve posted.
You installed a “lazy” plugin
the plugin added noscript tags to view-source
without the plugin, the page load is slow
The noscript tag “wraps” content that will display when JavaScript is not available.
The “lazy” suggests that the plugin queues loadiing page content until it is needed or perhaps in some other way to avoid “render blocking”.
Most site owners would want their pages to load as quickly as possible to lessen the chance that visitors would get impatient and leave, and would be less concerned about there being more tags in their HTML. So you can understand why gandalf458 is asking why you would want to remove them.
If this plugin is slowing down your website when it is supposed to be speeding it up then I can only presume that it isn’t very compatible with your theme.
In which case I would try using a different lazy load plugin.
I have heard good thing about one called “Lazy Load by WP Rocket”. It is made by the same people who make a premium catching plugin which a lot of people rave about.