Tikz edges drawn by foreach do not scale

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}[scale=0.5] % problem <---
        \tikzstyle{every node}=[draw,circle,fill=black,minimum size=4pt,
        inner sep=0pt]
        \node (a) at (0,0) {};
        \node (b) at (0,1) {};
        \node (c) at (0,2) {};
        \node (d) at (0,3) {};
        \node (e) at (1,1) {};
        \node (f) at (1,2) {};
        
        \foreach \x in {0,1,2,3}
        \foreach \y in {1,2}
        \draw (0, \x) -- (1, \y);
    \end{tikzpicture}

    \begin{tikzpicture}[scale=1.5] % problem <---
    \tikzstyle{every node}=[draw,circle,fill=black,minimum size=4pt,
    inner sep=0pt]
    \node (a) at (0,0) {};
    \node (b) at (0,1) {};
    \node (c) at (0,2) {};
    \node (d) at (0,3) {};
    \node (e) at (1,1) {};
    \node (f) at (1,2) {};
    
    \foreach \x in {0,1,2,3}
    \foreach \y in {1,2}
    \draw (0, \x) -- (1, \y);
\end{tikzpicture}
\end{document}

Just shorter code and correct syntax for defining nodes style. For exercise.

\documentclass[border=3.141592]{standalone}
\usepackage{tikz}

\begin{document}
    \begin{tikzpicture}[scale=0.5]% <--- scaling is not problem 
\tikzset{every node/.style = {circle, fill=black, minimum size=4pt, % <---
                              inner sep=0pt, outer sep=0pt}}
\foreach \i in {0,1,2,3}
    \foreach \j in {1,2}
{
\draw[red]   (0,\i) node {} -- (1,\j) node {};
}
    \end{tikzpicture}
\end{document}

Edit: In the case, if like to have named nodes, just add names to nodes. For example:

\documentclass[border=3.141592]{standalone}
\usepackage{tikz}

\begin{document}
    \begin{tikzpicture}[scale=0.5]% <--- scaling is not problem 
\tikzset{
    every node/.style = {circle, fill=black, minimum size=4pt, 
                         inner sep=0pt, outer sep=0pt}
        }
\foreach \i in {0,1,2,3}
    \foreach \j in {1,2}
{
\draw[red]   (0,\i) node (a\i) {} -- (1,\j) node (b\j) {};
}
\draw[blue] (a0) -- (a1);
    \end{tikzpicture}
\end{document}