Despite you beginning your question by mentioning the stupidity of people who disagree with you, and since the weather is not too good today, I’ll start a proper conversation and, out of interest, see how long it takes to degenerate into further insults.
//What UK exporters also need to be aware of is that each EU country is a sovereign nation and as such can set their own checks criteria on goods arriving from outside the EU//
Most of the product rules are harmonised in the EU. This means that the same rules apply in all EU countries. Rules are applied to product groups, such as food, toys, or electrical goods. Others are covered by harmonised product characteristics. This means a UK exporter selling those goods to EU countries needs to comply with just one set of standards. Where a product is not covered by this harmonisation, the seller has only to comply with the standards set by the individual country or countries he intends to sell them to. But the important point (as far as your statement above goes) is that this situation prevailed whilst we were EU members and still applies today to the remaining 27 members. If a German trader wants to sell goods not covered by the harmonisation rules to multiple EU countries he has to comply with the standards set by each of those countries and is thus in the same position as a UK trader.
Of course whilst the UK was a member of the EU it had to accept EU standards where they were harmonised and could not set its own standards. Now it can.
Incredible as it may seem, the rest of the world (the vast majority of countries) seems to manage perfectly well without a single market and customs union and no other group of countries has attempted to replicate the EU model. The UK has decided to join them.