Specific vendors did not start charging sales tax because someone posted something on a public forum. Anyone who believes that is the reason ... they are misinformed. Read the tax law and understand what your referring to before making false statements such as that.
It's really quite simple... there are thresholds to meet in the number of transactions to this state and/or the amount of sales being done in this state. Breach those thresholds and they must collect NJ state sales tax. Saying some business started collecting sales tax because someone talked about it in a forum is a moronic statement.
Economic Threshold
Consistent with Wayfair, legislation was enacted that requires certain remote sellers to collect and remit New Jersey Sales Tax. For sales made on and after November 1, 2018, a remote seller that makes a retail sale of tangible personal property, specified digital products, or services delivered into New Jersey must register, collect, and remit New Jersey Sales Tax if the remote seller meets either of the following criteria (the economic threshold):
The remote seller's gross revenue from sales of tangible personal property, specified digital products, or services delivered into New Jersey during the current or prior calendar year, exceeds $100,000; or
The remote seller sold tangible personal property, specified digital products, or services delivered into New Jersey in 200 or more separate transactions during the current or prior calendar year.
A remote seller that does not meet either of these criteria does not have to register with the Division of Taxation to collect and remit New Jersey Sales Tax.