Bearing in mind that the cookie plays a lot of important roles in web experience and improvements, however, my question is why are the visitor/users of most websites with the cookie popup forced to "Accept and Continue" without an option in form of a button/link to Decline and is this right by the laws guiding cookie usage.
GDPR is the main influencer with a mix of vested interest of the business.
GDPR requires a users to now consent to non essential cookies. If you do not consent then they cant be used and the business in question must provide you with a fully functioning website that uses only the essential cookies.
The business want you to accept and will try to encourage that as its in their interest to use and collect your data in order to tailor it better. If you decline they loose out on this so they try and force you down the 'Accept and Continue" route, which is allowed legally.
You can read more on it here.
I really hate the way most businesses go about GDPR compliance. Basically, you must explicitly agree to the use of tracking and communications for the tools you use.
"Compliance" has been taken to mean that you've been informed that you'll be tracked and continued use constitutes agreement. This is NOT the sentiment of the law. The expectation is to provide more granular controls to still allow use but the ability to opt in or out of specific tracking methods.
Most businesses fail at that, either because they don't want to spend the effort on tech to make that granular OR because they're unwilling/incapable of selling the user on the value they'll receive.
Would go a long way toward improving user satisfaction and granting users control over their privacy.
Unfortunately, that requires build time to enable/disable features and willingness to "sell" features to users. Blanket statements are easier to implement and you can likely avoid penalties from the EU even if you're not meeting the spirit of the law.
why are the visitor/users of most websites with the cookie popup forced to "Accept and Continue" without an option in form of a button/link to Decline
There often is an option to decline, which either is a link to Google or the sentence "leave the site". This is in almost all cases no opt-out, as such sites created (even 3rd-party) cookies, which are not deleted when you leave the site. So e.g Google analytics loaded at site B knows your were at site A, even when you immediately left site A when seeing the banner telling you "To opt-out leave the site". Which is not compliant to the law, but I do not know any case where someone got sued over this, either.
and is this right by the laws guiding cookie usage.
It is not. But before GDPR, only few countries had enforceable laws covering this and with GDPR many sites still think their "cookie banner" covers the legal issues. You may have noticed, that some of the big players added GDPR-walls instead of banners, because the new law includes costly penalties, so they do not want to be the first one to be sued for now respecting the law.
I asked for more details on GDPR walls on law.stackexchange.com, maybe you are interested in the question and the answers there.
For GDPR compliance you cannot track a user unless he hits the "Accept & Continue".
So it is perfectly legal to not have a "Decline" button as you are not supposed to track a user unless the user "Accepts".
So most of the websites will hide the decline button and make the Cookie popup annoying enough so that as a visitor there is a huge chance you end up Accepting only so that you can get a full screen experience.
A lot on this subject you can find here. GDPR & Consent BrianClifton