Because it's not true.
The Portuguese are NOT having second thoughts on the matter.
There is a poorly sourced, vague article on the Washington Post.
I've just read this article.
It contains two "criticisms".
First Porto's well connected mayor, Rui Moreira, and his people, saying that the problem is out of control. It very likely is, in Porto. I live there and it's kind of shit since the pandemic.
The second one (and in my view the only one that matters) is by the architect of the program Joao Goulao.
"João Goulão — head of Portugal’s national institute on drug use and the architect of decriminalization — admitted to the local press in December that “what we have today no longer serves as an example to anyone.” Rather than fault the policy, however, he blames a lack of funding.
After years of economic crisis, Portugal decentralized its drug oversight operation in 2012. A funding drop from 76 million euros ($82.7 million) to 16 million euros ($17.4 million) forced Portugal’s main institution to outsource work previously done by the state to nonprofit groups, including the street teams that engage with people who use drugs."
So yeah here's the thing.
No one is having second thoughts about the program, they've just massively defunded it to the point its architect says it barely works, and the Porto mayor got to complain about it to the Washington Post, likely because he has a really good PR company.
Rui Moreira is not part of any major political party.
No major politician is ever quoted in the article.
No data is shown on the topic showing that the Portuguese population is turning against the program.
So the statement that "The Portuguese are having second thoughts on the matter" remains completely unsourced.